diff --git a/.rubocop.yml b/.rubocop.yml
index 25c18ef643..b76c048511 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -18,12 +18,18 @@ Lint/UnusedBlockArgument:
   Exclude:
     - config/environments/*
 
+Lint/MissingSuper:
+  Enabled: false
+
 Style/HashEachMethods:
   Enabled: true
 
 Style/HashTransformKeys:
   Enabled: true
 
+Style/StringConcatenation:
+  Enabled: false
+
 Style/HashTransformValues:
   Enabled: true
 
diff --git a/Gemfile.lock b/Gemfile.lock
index 044fddbb8a..e79948bfcf 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -351,7 +351,7 @@ GEM
     rack (2.2.3)
     rack-attack (6.5.0)
       rack (>= 1.0, < 3)
-    rack-oauth2 (1.16.0)
+    rack-oauth2 (1.17.0)
       activesupport
       attr_required
       httpclient
@@ -359,7 +359,7 @@ GEM
       rack (>= 2.1.0)
     rack-protection (2.1.0)
       rack
-    rack-proxy (0.6.5)
+    rack-proxy (0.7.0)
       rack
     rack-rewrite (1.5.1)
     rack-test (1.1.0)
@@ -439,31 +439,32 @@ GEM
     rspec-support (3.10.2)
     rspec_junit_formatter (0.4.1)
       rspec-core (>= 2, < 4, != 2.12.0)
-    rubocop (0.87.1)
+    rubocop (1.15.0)
       parallel (~> 1.10)
-      parser (>= 2.7.1.1)
+      parser (>= 3.0.0.0)
       rainbow (>= 2.2.2, < 4.0)
-      regexp_parser (>= 1.7)
+      regexp_parser (>= 1.8, < 3.0)
       rexml
-      rubocop-ast (>= 0.1.0, < 1.0)
+      rubocop-ast (>= 1.5.0, < 2.0)
       ruby-progressbar (~> 1.7)
-      unicode-display_width (>= 1.4.0, < 2.0)
-    rubocop-ast (0.8.0)
-      parser (>= 2.7.1.5)
-    rubocop-govuk (3.17.2)
-      rubocop (= 0.87.1)
-      rubocop-ast (= 0.8.0)
-      rubocop-rails (= 2.8.1)
+      unicode-display_width (>= 1.4.0, < 3.0)
+    rubocop-ast (1.6.0)
+      parser (>= 3.0.1.1)
+    rubocop-govuk (4.0.0)
+      rubocop (~> 1.15.0)
+      rubocop-ast (~> 1.6.0)
+      rubocop-rails (~> 2.10.0)
       rubocop-rake (= 0.5.1)
-      rubocop-rspec (= 1.42.0)
-    rubocop-rails (2.8.1)
+      rubocop-rspec (~> 2.3.0)
+    rubocop-rails (2.10.1)
       activesupport (>= 4.2.0)
       rack (>= 1.1)
-      rubocop (>= 0.87.0)
+      rubocop (>= 1.7.0, < 2.0)
     rubocop-rake (0.5.1)
       rubocop
-    rubocop-rspec (1.42.0)
-      rubocop (>= 0.87.0)
+    rubocop-rspec (2.3.0)
+      rubocop (~> 1.0)
+      rubocop-ast (>= 1.1.0)
     ruby-graphviz (1.2.5)
       rexml
     ruby-progressbar (1.11.0)
@@ -532,7 +533,7 @@ GEM
     tzinfo (2.0.4)
       concurrent-ruby (~> 1.0)
     uk_postcode (2.1.6)
-    unicode-display_width (1.7.0)
+    unicode-display_width (2.0.0)
     uniform_notifier (1.14.2)
     validate_email (0.1.6)
       activemodel (>= 3.0)
@@ -563,7 +564,7 @@ GEM
       rack-proxy (>= 0.6.1)
       railties (>= 5.2)
       semantic_range (>= 2.3.0)
-    websocket-driver (0.7.3)
+    websocket-driver (0.7.5)
       websocket-extensions (>= 0.1.0)
     websocket-extensions (0.1.5)
     xpath (3.2.0)
diff --git a/app/controllers/candidates/schools_controller.rb b/app/controllers/candidates/schools_controller.rb
index 34a26fee5b..dac3c3f853 100644
--- a/app/controllers/candidates/schools_controller.rb
+++ b/app/controllers/candidates/schools_controller.rb
@@ -40,7 +40,7 @@ def show
 
   def location_present?
     search_params[:location].present? || (
-      search_params[:latitude].present? && search_params[:latitude].present?
+      search_params[:longitude].present? && search_params[:latitude].present?
     )
   end
 
diff --git a/app/controllers/concerns/gitis_authentication.rb b/app/controllers/concerns/gitis_authentication.rb
index bd6db92609..25f702bef0 100644
--- a/app/controllers/concerns/gitis_authentication.rb
+++ b/app/controllers/concerns/gitis_authentication.rb
@@ -3,7 +3,9 @@ module GitisAuthentication
   include GitisAccess
 
   class UnauthorizedCandidate < RuntimeError; end
+
   class UnconfirmedCandidate < RuntimeError; end
+
   class InvalidContact < RuntimeError; end
 
   included do
diff --git a/app/controllers/schools/base_controller.rb b/app/controllers/schools/base_controller.rb
index a9395600c7..07451935d9 100644
--- a/app/controllers/schools/base_controller.rb
+++ b/app/controllers/schools/base_controller.rb
@@ -1,5 +1,6 @@
 module Schools
   class SchoolNotRegistered < StandardError; end
+
   class MissingURN < StandardError; end
 
   class BaseController < ApplicationController
@@ -23,7 +24,7 @@ class BaseController < ApplicationController
 
     def current_school
       if current_urn.blank?
-        sub = current_user.raw_attributes.dig("sub")
+        sub = current_user.raw_attributes["sub"]
         raise MissingURN, "school urn is missing, unable to match with school for - user #{sub}"
       end
 
@@ -44,7 +45,7 @@ def set_site_header_text
 
     def retrieve_school(urn)
       if urn.blank?
-        sub = current_user.raw_attributes.dig("sub")
+        sub = current_user.raw_attributes["sub"]
         raise MissingURN, "school urn is missing, unable to match with school for - user #{sub}"
       end
 
diff --git a/app/controllers/schools/insecure_sessions_controller.rb b/app/controllers/schools/insecure_sessions_controller.rb
index 703e8167c3..df60e16793 100644
--- a/app/controllers/schools/insecure_sessions_controller.rb
+++ b/app/controllers/schools/insecure_sessions_controller.rb
@@ -8,7 +8,7 @@ def create
 
     session[:id_token]     = 'abc123'
 
-    # NOTE the sub (subscription) param is the user's unique identifier
+    # NOTE: the sub (subscription) param is the user's unique identifier
     # on DfE Sign-in and is hard-coded here. It must match the corresponding
     # value injected into Schools::SessionsController
     session[:current_user] = OpenIDConnect::ResponseObject::UserInfo.new(
diff --git a/app/controllers/schools/sessions_controller.rb b/app/controllers/schools/sessions_controller.rb
index c055dc8706..53da361cee 100644
--- a/app/controllers/schools/sessions_controller.rb
+++ b/app/controllers/schools/sessions_controller.rb
@@ -1,8 +1,12 @@
 module Schools
   class StateMismatchError < StandardError; end
+
   class AuthFailedError < StandardError; end
+
   class InsufficientPrivilegesError < StandardError; end
+
   class SessionExpiredError < StandardError; end
+
   class NoOrganisationError < StandardError; end
 
   class SessionsController < ApplicationController
diff --git a/app/helpers/schools/confirm_attendance_helper.rb b/app/helpers/schools/confirm_attendance_helper.rb
index b2d3948630..3b5c0cd526 100644
--- a/app/helpers/schools/confirm_attendance_helper.rb
+++ b/app/helpers/schools/confirm_attendance_helper.rb
@@ -1,5 +1,5 @@
 module Schools::ConfirmAttendanceHelper
-  # note we can't use the form builder here because it wraps everything in
+  # NOTE: we can't use the form builder here because it wraps everything in
   # form-groups and fieldsets which affect how it's displayed in a table cell
   def confirm_attendance_radio(builder, booking_id, value, label_text)
     tag.div(class: "govuk-radios__item") do
diff --git a/app/models/bookings/data/school_mass_importer.rb b/app/models/bookings/data/school_mass_importer.rb
index fa5e47a9dc..78977c1837 100644
--- a/app/models/bookings/data/school_mass_importer.rb
+++ b/app/models/bookings/data/school_mass_importer.rb
@@ -113,7 +113,7 @@ def cleanup_website(urn, url)
         return nil if url_with_prefix =~ /@/
 
         # skip urls that don't look sensible
-        unless url_with_prefix.match?(/^(http|https):\/\/[a-z0-9]+([\-\.]{1}[a-z0-9]+)*\.[a-z]{2,10}(:[0-9]{1,5})?(\/.*)?$/ix)
+        unless url_with_prefix.match?(/^(http|https):\/\/[a-z0-9]+([\-.]{1}[a-z0-9]+)*\.[a-z]{2,10}(:[0-9]{1,5})?(\/.*)?$/ix)
           Rails.logger.info "invalid website for #{urn}, #{url}"
           return nil
         end
diff --git a/app/models/bookings/profile_attributes_convertor.rb b/app/models/bookings/profile_attributes_convertor.rb
index 9af44be7e0..fc3df45fa4 100644
--- a/app/models/bookings/profile_attributes_convertor.rb
+++ b/app/models/bookings/profile_attributes_convertor.rb
@@ -49,9 +49,10 @@ def phase_ids
     def convert_dbs_profile
       output[:dbs_policy_conditions] = input[:dbs_requirement_dbs_policy_conditions]
 
-      output[:dbs_policy_details] = if input[:dbs_requirement_dbs_policy_conditions] == 'notrequired'
+      output[:dbs_policy_details] = case input[:dbs_requirement_dbs_policy_conditions]
+                                    when 'notrequired'
                                       input[:dbs_requirement_no_dbs_policy_details].presence
-                                    elsif input[:dbs_requirement_dbs_policy_conditions] == 'inschool'
+                                    when 'inschool'
                                       input[:dbs_requirement_dbs_policy_details_inschool].presence
                                     else
                                       input[:dbs_requirement_dbs_policy_details].presence
diff --git a/app/models/bookings/school_search.rb b/app/models/bookings/school_search.rb
index 0935312be4..9aadc8d94c 100644
--- a/app/models/bookings/school_search.rb
+++ b/app/models/bookings/school_search.rb
@@ -167,7 +167,7 @@ def valid_geocoder_result?(result)
 
   def order_by(option)
     if (option == 'distance') && coordinates.present?
-      # note distance isn't actually an attribute of
+      # NOTE: distance isn't actually an attribute of
       # Bookings::School so we can't use hash syntax
       # as Rails will complain
       'distance asc'
diff --git a/app/models/bookings/school_sync.rb b/app/models/bookings/school_sync.rb
index 2c3fec3aaa..451b79dcfa 100644
--- a/app/models/bookings/school_sync.rb
+++ b/app/models/bookings/school_sync.rb
@@ -40,7 +40,7 @@ def import_and_update
   end
 
   def sync_disabled?
-    disabled = ENV.fetch('GIAS_SYNC_DISABLED') { false }
+    disabled = ENV.fetch('GIAS_SYNC_DISABLED', false)
     disabled.to_s.in?(%w[1 true yes])
   end
 
diff --git a/app/models/cookie_preference.rb b/app/models/cookie_preference.rb
index ecdfcc80d2..78620cac8f 100644
--- a/app/models/cookie_preference.rb
+++ b/app/models/cookie_preference.rb
@@ -74,7 +74,7 @@ def rejected_cookies
     all_cookies - accepted_cookies
   end
 
-  # Note: allowed is not the same as accepted
+  # NOTE: allowed is not the same as accepted
   # allowed = 'not explicitly rejected, and maybe explicitly accepted'
   # accepted = 'explicitly accepted'
   def allowed?(cookie_category_or_name)
diff --git a/app/models/schools/on_boarding/profile_subject.rb b/app/models/schools/on_boarding/profile_subject.rb
index 4f958ed8b5..f39c081726 100644
--- a/app/models/schools/on_boarding/profile_subject.rb
+++ b/app/models/schools/on_boarding/profile_subject.rb
@@ -13,5 +13,5 @@ class Schools::OnBoarding::ProfileSubject < ApplicationRecord
   validates :subject, presence: true
 
   validates :schools_school_profile_id,
-    uniqueness: { scope: %i[bookings_subject_id] }
+    uniqueness: { scope: :bookings_subject_id }
 end
diff --git a/app/presenters/candidates/school_presenter.rb b/app/presenters/candidates/school_presenter.rb
index bb7047f2e4..3718ed444a 100644
--- a/app/presenters/candidates/school_presenter.rb
+++ b/app/presenters/candidates/school_presenter.rb
@@ -97,22 +97,19 @@ def secondary_dates_grouped_by_date
   private
 
     def dbs_requirement
-      case profile.dbs_policy_conditions
-      when "required"
-        "Yes"
-      when "inschool"
-        "Yes - when in school"
-      when "notrequired"
-        'No - Candidates will be accompanied at all times when in school'
-      end
+      {
+        'required' => 'Yes',
+        'inschool' => 'Yes - when in school',
+        'notrequired' => 'No - Candidates will be accompanied at all times when in school'
+      }[profile.dbs_policy_conditions]
     end
 
     def legacy_dbs_requirement
-      case profile.dbs_required
-      when 'always' then 'Yes - Always'
-      when 'sometimes' then 'Yes - Sometimes'
-      when 'never' then 'No - Candidates will be accompanied at all times'
-      end
+      {
+        'always' => 'Yes - Always',
+        'sometimes' => 'Yes - Sometimes',
+        'never' => 'No - Candidates will be accompanied at all times'
+      }[profile.dbs_required]
     end
   end
 end
diff --git a/app/services/bookings/gitis/api.rb b/app/services/bookings/gitis/api.rb
index 5f3dca47cb..8685817990 100644
--- a/app/services/bookings/gitis/api.rb
+++ b/app/services/bookings/gitis/api.rb
@@ -60,6 +60,7 @@ def patch(url, params, headers = {})
     end
 
     class UnsupportedAbsoluteUrlError < RuntimeError; end
+
     class ConnectionFailed < RuntimeError
       def initialize(url)
         super "Connection Failed: #{url}"
@@ -78,6 +79,7 @@ def initialize(resp)
     end
 
     class UnknownUrlError < BadResponseError; end
+
     class AccessDeniedError < BadResponseError; end
 
   private
@@ -139,7 +141,7 @@ def parse_response(resp)
     end
 
     def parse_entity_id(entity_id)
-      entity_id&.gsub(%r{\A#{endpoint_url}\/}, '')
+      entity_id&.gsub(%r{\A#{endpoint_url}/}, '')
     end
   end
 end
diff --git a/app/services/bookings/gitis/auth.rb b/app/services/bookings/gitis/auth.rb
index e3ea6c957c..060947b3d5 100644
--- a/app/services/bookings/gitis/auth.rb
+++ b/app/services/bookings/gitis/auth.rb
@@ -29,7 +29,7 @@ def config
         Rails.application.config.x.gitis
       end
 
-      def token(force_reload = false)
+      def token(force_reload: false)
         if !force_reload && (cached_token = fetch_cached_token) && cached_token.present?
           cached_token
         elsif (new_token = retrieve_token)
diff --git a/app/services/bookings/gitis/entity.rb b/app/services/bookings/gitis/entity.rb
index f70d1212ec..edd9816f43 100644
--- a/app/services/bookings/gitis/entity.rb
+++ b/app/services/bookings/gitis/entity.rb
@@ -1,6 +1,8 @@
 module Bookings::Gitis
   class IdChangedUnexpectedly < RuntimeError; end
+
   class MissingPrimaryKey < RuntimeError; end
+
   class InvalidEntityId < RuntimeError; end
 
   class InvalidEntity < RuntimeError
@@ -17,7 +19,7 @@ module Entity
     include ActiveModel::Dirty
 
     ID_FORMAT = /\A[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}\z/.freeze
-    BIND_FORMAT = /\A[^\(]+\([0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}\)\z/.freeze
+    BIND_FORMAT = /\A[^(]+\([0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}\)\z/.freeze
 
     def self.valid_id?(id)
       ID_FORMAT.match? id.to_s
diff --git a/app/services/bookings/gitis/factory.rb b/app/services/bookings/gitis/factory.rb
index 47f658a07a..6a29936065 100644
--- a/app/services/bookings/gitis/factory.rb
+++ b/app/services/bookings/gitis/factory.rb
@@ -14,7 +14,7 @@ def crm(read_from_cache: false)
         if Rails.application.config.x.gitis.fake_crm
           Bookings::Gitis::FakeCrm.new
         elsif Rails.application.config.x.gitis.caching
-          Bookings::Gitis::CRM.new caching_store(read_from_cache)
+          Bookings::Gitis::CRM.new caching_store(read_from_cache: read_from_cache)
         else
           Bookings::Gitis::CRM.new store
         end
@@ -42,7 +42,7 @@ def read_write_caching_store
           store, cache, namespace: NAMESPACE, ttl: TTL, version: VERSION
       end
 
-      def caching_store(read_from_cache = false)
+      def caching_store(read_from_cache: false)
         read_from_cache ? read_write_caching_store : write_only_caching_store
       end
 
diff --git a/app/services/bookings/gitis/store/write_only_cache.rb b/app/services/bookings/gitis/store/write_only_cache.rb
index f688a8cbe7..2b4379cb5f 100644
--- a/app/services/bookings/gitis/store/write_only_cache.rb
+++ b/app/services/bookings/gitis/store/write_only_cache.rb
@@ -3,6 +3,7 @@ module Gitis
     module Store
       class WriteOnlyCache
         attr_reader :store, :cache, :namespace, :ttl, :version
+
         delegate :fetch, to: :store
 
         def initialize(store, cache, namespace: nil, ttl: 1.hour, version: 'v1')
diff --git a/app/services/candidates/registrations/registration_session.rb b/app/services/candidates/registrations/registration_session.rb
index 719b76c898..d27ef9f29f 100644
--- a/app/services/candidates/registrations/registration_session.rb
+++ b/app/services/candidates/registrations/registration_session.rb
@@ -5,6 +5,7 @@ module Candidates
   module Registrations
     class RegistrationSession
       class NotCompletedError < StandardError; end
+
       class StepNotFound < StandardError; end
 
       PENDING_EMAIL_CONFIRMATION_STATUS = 'pending_email_confirmation'.freeze
diff --git a/app/services/candidates/registrations/registration_store.rb b/app/services/candidates/registrations/registration_store.rb
index 9b890760b8..be17e872f3 100644
--- a/app/services/candidates/registrations/registration_store.rb
+++ b/app/services/candidates/registrations/registration_store.rb
@@ -5,6 +5,7 @@ class RegistrationStore
       include Singleton
 
       class SessionNotFound < StandardError; end
+
       class NoKey < StandardError; end
 
       def initialize
diff --git a/app/validators/email_format_validator.rb b/app/validators/email_format_validator.rb
index 2cecff0605..9b2a608e72 100644
--- a/app/validators/email_format_validator.rb
+++ b/app/validators/email_format_validator.rb
@@ -1,5 +1,5 @@
 class EmailFormatValidator < ActiveModel::EachValidator
-  EMAIL_WITH_FULLY_QUALIFIED_HOSTNAME = %r{\A[^\s@]+@[^\.\s]+\.[^\s]+\z}.freeze
+  EMAIL_WITH_FULLY_QUALIFIED_HOSTNAME = %r{\A[^\s@]+@[^.\s]+\.[^\s]+\z}.freeze
 
   def validate_each(record, attribute, value)
     unless value.present? && is_an_email_uri?(value) && is_fqdn?(value)
diff --git a/bin/update b/bin/update
deleted file mode 100755
index 67d0d49645..0000000000
--- a/bin/update
+++ /dev/null
@@ -1,28 +0,0 @@
-#!/usr/bin/env ruby
-require 'fileutils'
-include FileUtils
-
-# path to your application root.
-APP_ROOT = File.expand_path('..', __dir__)
-
-def system!(*args)
-  system(*args) || abort("\n== Command #{args} failed ==")
-end
-
-chdir APP_ROOT do
-  # This script is a way to update your development environment automatically.
-  # Add necessary update steps to this file.
-
-  puts '== Installing dependencies =='
-  system! 'gem install bundler --conservative'
-  system('bundle check') || system!('bundle install')
-
-  puts "\n== Updating database =="
-  system! 'bin/rails db:migrate'
-
-  puts "\n== Removing old logs and tempfiles =="
-  system! 'bin/rails log:clear tmp:clear'
-
-  puts "\n== Restarting application server =="
-  system! 'bin/rails restart'
-end
diff --git a/config/environments/development.rb b/config/environments/development.rb
index f8be319c10..a0213e1c77 100644
--- a/config/environments/development.rb
+++ b/config/environments/development.rb
@@ -86,13 +86,13 @@
     Bullet.unused_eager_loading_enable = false
   end
 
-  config.x.phase = Integer(ENV.fetch('PHASE') { 10_000 })
+  config.x.phase = Integer(ENV.fetch('PHASE', 10_000))
   config.x.features = %i[
     subject_specific_dates
     capped_bookings
   ]
   config.x.candidates.deactivate_applications = ENV['DEACTIVATE_CANDIDATES'].to_s.presence || false
-  config.x.google_maps_key = ENV['GOOGLE_MAPS_KEY'].presence || Rails.application.credentials.dig(:google_maps_key)
+  config.x.google_maps_key = ENV['GOOGLE_MAPS_KEY'].presence || Rails.application.credentials[:google_maps_key]
 
   # dfe signin redirects back to https, so force it
   config.force_ssl = true
@@ -100,7 +100,7 @@
   # dfe signin config, should be in credentials or env vars
   config.x.base_url = 'https://localhost:3000'
   config.x.oidc_client_id = 'schoolexperience'
-  config.x.oidc_client_secret = Rails.application.credentials.dig(:dfe_pp_signin_secret)
+  config.x.oidc_client_secret = Rails.application.credentials[:dfe_pp_signin_secret]
   config.x.oidc_host = 'pp-oidc.signin.education.gov.uk'
   config.x.oidc_services_list_url = 'https://pp-services.signin.education.gov.uk/my-services'
   config.x.dfe_sign_in_api_host = 'pp-api.signin.education.gov.uk'
@@ -116,7 +116,7 @@
     Rails.application.config.x.notify_client = ENV['NOTIFY_CLIENT']
   end
 
-  config.x.gitis.fake_crm = truthy_strings.include?(String(ENV.fetch('FAKE_CRM') { true }))
+  config.x.gitis.fake_crm = truthy_strings.include?(String(ENV.fetch('FAKE_CRM', true)))
   config.x.gitis.fake_crm_uuid = ENV.fetch('FAKE_CRM_UUID', nil)
   config.x.gitis.auth_client_id = ENV.fetch('CRM_CLIENT_ID', 'notset')
   config.x.gitis.auth_secret = ENV.fetch('CRM_CLIENT_SECRET', 'notset')
diff --git a/config/environments/production.rb b/config/environments/production.rb
index cd83cfa1e5..03a1ca5032 100644
--- a/config/environments/production.rb
+++ b/config/environments/production.rb
@@ -85,7 +85,7 @@
   # config.logger = ActiveSupport::TaggedLogging.new(Syslog::Logger.new 'app-name')
 
   if ENV["RAILS_LOG_TO_STDOUT"].present?
-    logger           = ActiveSupport::Logger.new(STDOUT)
+    logger           = ActiveSupport::Logger.new($stdout)
     logger.formatter = config.log_formatter
     config.logger    = ActiveSupport::TaggedLogging.new(logger)
   end
@@ -138,7 +138,7 @@
   config.x.default_phase = 4
   config.x.phase = Integer(ENV['PHASE'].presence || config.x.default_phase)
   config.x.candidates.deactivate_applications = ENV['DEACTIVATE_CANDIDATES'].to_s.presence || false
-  config.x.google_maps_key = ENV['GOOGLE_MAPS_KEY'].presence || Rails.application.credentials.dig(:google_maps_key)
+  config.x.google_maps_key = ENV['GOOGLE_MAPS_KEY'].presence || Rails.application.credentials[:google_maps_key]
 
   config.x.base_url = ENV.fetch('DFE_SIGNIN_BASE_URL') { 'https://schoolexperience.education.gov.uk' }
   config.x.oidc_client_id = ENV.fetch('DFE_SIGNIN_CLIENT_ID') { 'schoolexperience' }
diff --git a/config/environments/servertest.rb b/config/environments/servertest.rb
index e2b796e776..685aa5b623 100644
--- a/config/environments/servertest.rb
+++ b/config/environments/servertest.rb
@@ -23,9 +23,9 @@
   config.x.google_maps_key = nil
 
   # dfe signin config, should be in credentials or env vars
-  config.x.base_url = "https://localhost:#{ENV.fetch('PORT') { 3000 }}"
+  config.x.base_url = "https://localhost:#{ENV.fetch('PORT', 3000)}"
   config.x.oidc_client_id = 'schoolexperience'
-  config.x.oidc_client_secret = Rails.application.credentials.dig(:dfe_pp_signin_secret)
+  config.x.oidc_client_secret = Rails.application.credentials[:dfe_pp_signin_secret]
   config.x.oidc_host = 'pp-oidc.signin.education.gov.uk'
   config.x.oidc_services_list_url = 'https://some-oidc.provider.com/my-services'
   config.x.dfe_sign_in_api_host = 'pp-api.signin.education.gov.uk'
diff --git a/config/initializers/canonical_redirect.rb b/config/initializers/canonical_redirect.rb
index 20d63b2afd..ea0e637f30 100644
--- a/config/initializers/canonical_redirect.rb
+++ b/config/initializers/canonical_redirect.rb
@@ -16,7 +16,7 @@
       if: proc { |rack_env|
         ENV['CANONICAL_DOMAIN'].present? &&
           rack_env['HTTP_HOST'] != ENV['CANONICAL_DOMAIN'] &&
-          !rack_env['PATH_INFO'].match?(%r{/(healthcheck|deployment|healthchecks\/[a-z]+)\.txt})
+          !rack_env['PATH_INFO'].match?(%r{/(healthcheck|deployment|healthchecks/[a-z]+)\.txt})
       }
   end
 end
diff --git a/config/puma.rb b/config/puma.rb
index ba5791011f..94a2893a69 100644
--- a/config/puma.rb
+++ b/config/puma.rb
@@ -4,8 +4,8 @@
 # the maximum value specified for Puma. Default is set to 5 threads for minimum
 # and maximum; this matches the default thread size of Active Record.
 #
-max_threads_count = ENV.fetch("RAILS_MAX_THREADS") { 5 }
-min_threads_count = ENV.fetch("RAILS_MIN_THREADS") { max_threads_count }
+max_threads_count = ENV.fetch("RAILS_MAX_THREADS", 5)
+min_threads_count = ENV.fetch("RAILS_MIN_THREADS", max_threads_count)
 threads min_threads_count, max_threads_count
 
 # Specifies the `worker_timeout` threshold that Puma will use to wait before
@@ -15,14 +15,14 @@
 
 # Specifies the `port` that Puma will listen on to receive requests; default is 3000.
 #
-listen_port = ENV.fetch("PORT") { 3000 }
+listen_port = ENV.fetch("PORT", 3000)
 
 # Specifies the `environment` that Puma will run in.
 #
-environment ENV.fetch("RAILS_ENV") { "development" }
+environment ENV.fetch("RAILS_ENV", "development")
 
 # Specifies the `pidfile` that Puma will use.
-pidfile ENV.fetch("PIDFILE") { "tmp/pids/server.pid" }
+pidfile ENV.fetch("PIDFILE", "tmp/pids/server.pid")
 
 # Specifies the number of `workers` to boot in clustered mode.
 # Workers are forked web server processes. If using threads and workers together
diff --git a/db/migrate/20210622134457_add_unique_index_to_booking_cancellations.rb b/db/migrate/20210622134457_add_unique_index_to_booking_cancellations.rb
new file mode 100644
index 0000000000..f4fa720244
--- /dev/null
+++ b/db/migrate/20210622134457_add_unique_index_to_booking_cancellations.rb
@@ -0,0 +1,11 @@
+class AddUniqueIndexToBookingCancellations < ActiveRecord::Migration[6.1]
+  def up
+    remove_index :bookings_placement_request_cancellations, name: "index_cancellations_on_bookings_placement_request_id"
+    add_index :bookings_placement_request_cancellations, :bookings_placement_request_id, name: "index_cancellations_on_bookings_placement_request_id", unique: true
+  end
+
+  def down
+    remove_index :bookings_placement_request_cancellations, name: "index_cancellations_on_bookings_placement_request_id"
+    add_index :bookings_placement_request_cancellations, :bookings_placement_request_id, name: "index_cancellations_on_bookings_placement_request_id"
+  end
+end
diff --git a/db/migrate/20210622155324_add_unique_index_to_bookings_schools_phases.rb b/db/migrate/20210622155324_add_unique_index_to_bookings_schools_phases.rb
new file mode 100644
index 0000000000..1d9a21b86f
--- /dev/null
+++ b/db/migrate/20210622155324_add_unique_index_to_bookings_schools_phases.rb
@@ -0,0 +1,8 @@
+class AddUniqueIndexToBookingsSchoolsPhases < ActiveRecord::Migration[6.1]
+  def change
+    add_index :bookings_schools_phases,
+      %i[bookings_school_id bookings_phase_id],
+      unique: true,
+      name: "index_bookings_schools_phases_school_id_and_phase_id"
+  end
+end
diff --git a/db/migrate/20210622160115_add_unique_index_to_schools_on_boarding_profile_subjects.rb b/db/migrate/20210622160115_add_unique_index_to_schools_on_boarding_profile_subjects.rb
new file mode 100644
index 0000000000..1a90a421d4
--- /dev/null
+++ b/db/migrate/20210622160115_add_unique_index_to_schools_on_boarding_profile_subjects.rb
@@ -0,0 +1,8 @@
+class AddUniqueIndexToSchoolsOnBoardingProfileSubjects < ActiveRecord::Migration[6.1]
+  def change
+    add_index :schools_on_boarding_profile_subjects,
+      %i[schools_school_profile_id bookings_subject_id],
+      unique: true,
+      name: "index_profile_subjects_school_profile_id_and_subject_id"
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index 54058f66a1..68f3c938ab 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 2021_01_30_095443) do
+ActiveRecord::Schema.define(version: 2021_06_22_160115) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -91,7 +91,7 @@
     t.text "extra_details"
     t.datetime "viewed_at"
     t.string "rejection_category"
-    t.index ["bookings_placement_request_id"], name: "index_cancellations_on_bookings_placement_request_id"
+    t.index ["bookings_placement_request_id"], name: "index_cancellations_on_bookings_placement_request_id", unique: true
     t.index ["rejection_category"], name: "index_bookings_placement_request_cancellations_category"
   end
 
@@ -238,6 +238,7 @@
     t.integer "bookings_phase_id", null: false
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
+    t.index ["bookings_school_id", "bookings_phase_id"], name: "index_bookings_schools_phases_school_id_and_phase_id", unique: true
   end
 
   create_table "bookings_schools_subjects", force: :cascade do |t|
@@ -319,6 +320,7 @@
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
     t.index ["bookings_subject_id"], name: "index_profile_subjects_on_school_profile_i"
+    t.index ["schools_school_profile_id", "bookings_subject_id"], name: "index_profile_subjects_school_profile_id_and_subject_id", unique: true
     t.index ["schools_school_profile_id"], name: "index_profile_subjects_on_school_profile_id"
   end
 
diff --git a/features/step_definitions/candidates/schools/show_steps.rb b/features/step_definitions/candidates/schools/show_steps.rb
index 84296ab24f..89dab1f2ee 100644
--- a/features/step_definitions/candidates/schools/show_steps.rb
+++ b/features/step_definitions/candidates/schools/show_steps.rb
@@ -169,9 +169,10 @@
 end
 
 Given("my school of choice has {string} dates") do |option|
-  @school = if option == 'fixed'
+  @school = case option
+            when 'fixed'
               FactoryBot.create(:bookings_school, :with_fixed_availability_preference)
-            elsif option == 'flexible'
+            when 'flexible'
               FactoryBot.create(:bookings_school)
             else
               raise 'invalid flexibility option'
diff --git a/features/step_definitions/schools/placement_request_steps.rb b/features/step_definitions/schools/placement_request_steps.rb
index 06589246aa..d8cbf21f73 100644
--- a/features/step_definitions/schools/placement_request_steps.rb
+++ b/features/step_definitions/schools/placement_request_steps.rb
@@ -127,7 +127,7 @@
 end
 
 Then("there should be the following buttons:") do |table|
-  # note that button_to inserts a form with a submit input so
+  # NOTE: that button_to inserts a form with a submit input so
   # if we don't find a regular link/button check for that too
   table.transpose.raw.flatten.each do |button_text|
     within('.accept-or-reject') do
diff --git a/features/support/database_cleaner.rb b/features/support/database_cleaner.rb
index ceb3df2013..b7900d1615 100644
--- a/features/support/database_cleaner.rb
+++ b/features/support/database_cleaner.rb
@@ -29,5 +29,5 @@
 DatabaseCleaner.strategy = :deletion, deletion_options
 Cucumber::Rails::Database.javascript_strategy = :deletion, deletion_options
 if ENV['DEBUG_DATABASE_CLEANER'].present?
-  ActiveRecord::Base.logger = Logger.new(STDOUT)
+  ActiveRecord::Base.logger = Logger.new($stdout)
 end
diff --git a/features/support/feature_helper.rb b/features/support/feature_helper.rb
index 2a0fbd8733..83f518ceee 100644
--- a/features/support/feature_helper.rb
+++ b/features/support/feature_helper.rb
@@ -1,5 +1,5 @@
 def delay_page_load
   if ENV['CUC_DRIVER'].present? || ENV['CUC_PAGE_DELAY'].present?
-    sleep Integer(ENV.fetch('CUC_PAGE_DELAY') { 0 })
+    sleep Integer(ENV.fetch('CUC_PAGE_DELAY', 0))
   end
 end
diff --git a/lib/notify/notify_sync.rb b/lib/notify/notify_sync.rb
index 2ff05c8fc0..0ee1822b09 100644
--- a/lib/notify/notify_sync.rb
+++ b/lib/notify/notify_sync.rb
@@ -34,7 +34,7 @@ def pull
       File.write(
         File.join(
           TEMPLATE_PATH,
-          [rt.name.gsub(/[\ ]/, "").underscore, template_id, 'md'].join('.'),
+          [rt.name.gsub(/\ /, "").underscore, template_id, 'md'].join('.'),
         ),
         reencode(rt.body)
       )
diff --git a/script/cleanse b/script/cleanse
index fe2663ef10..9ff26665b0 100755
--- a/script/cleanse
+++ b/script/cleanse
@@ -9,4 +9,4 @@
 #
 # $./cleanse < edubasealldata20190220.csv > clean.csv
 
-STDOUT.puts(STDIN.read.scrub.encode(Encoding::UTF_8, universal_newline: true))
+$stdout.puts($stdin.read.scrub.encode(Encoding::UTF_8, universal_newline: true))
diff --git a/spec/controllers/candidates/dashboard_base_controller_spec.rb b/spec/controllers/candidates/dashboard_base_controller_spec.rb
index 982b2c68b5..a61b43a2fe 100644
--- a/spec/controllers/candidates/dashboard_base_controller_spec.rb
+++ b/spec/controllers/candidates/dashboard_base_controller_spec.rb
@@ -1,12 +1,12 @@
 require 'rails_helper'
 
-RSpec.describe Candidates::DashboardBaseController, type: :request do
-  class StubController < Candidates::DashboardBaseController
-    def index
-      render plain: 'Authorized'
-    end
+class StubController < Candidates::DashboardBaseController
+  def index
+    render plain: 'Authorized'
   end
+end
 
+RSpec.describe Candidates::DashboardBaseController, type: :request do
   describe "GET #index" do
     before do
       Rails.application.routes.send(:eval_block, lambda {
diff --git a/spec/controllers/candidates/registrations/subject_and_date_informations_controller_spec.rb b/spec/controllers/candidates/registrations/subject_and_date_informations_controller_spec.rb
index a13d65f188..051482bc65 100644
--- a/spec/controllers/candidates/registrations/subject_and_date_informations_controller_spec.rb
+++ b/spec/controllers/candidates/registrations/subject_and_date_informations_controller_spec.rb
@@ -21,7 +21,7 @@
         it('responds with 302') { expect(response.status).to eq 302 }
 
         it 'should redirect to the personal information page' do
-          expect(response.header.dig("Location")).to end_with('schools/11048/registrations/personal_information/new')
+          expect(response.header["Location"]).to end_with('schools/11048/registrations/personal_information/new')
         end
       end
     end
diff --git a/spec/controllers/concerns/dfe_authentication_spec.rb b/spec/controllers/concerns/dfe_authentication_spec.rb
index 34af801c95..fecec15d70 100644
--- a/spec/controllers/concerns/dfe_authentication_spec.rb
+++ b/spec/controllers/concerns/dfe_authentication_spec.rb
@@ -28,7 +28,7 @@
         end
 
         it 'will request organisation from DfE Sign-in' do
-          is_expected.to redirect_to %r{\&scope=profile%20organisation%20openid}
+          is_expected.to redirect_to %r{&scope=profile%20organisation%20openid}
         end
       end
 
@@ -40,7 +40,7 @@
         end
 
         it 'will not request organisation from DfE Sign-in' do
-          is_expected.to redirect_to %r{\&scope=profile%20openid}
+          is_expected.to redirect_to %r{&scope=profile%20openid}
         end
       end
     end
diff --git a/spec/controllers/concerns/gitis_access_spec.rb b/spec/controllers/concerns/gitis_access_spec.rb
index 638b1c8099..7e2184f543 100644
--- a/spec/controllers/concerns/gitis_access_spec.rb
+++ b/spec/controllers/concerns/gitis_access_spec.rb
@@ -1,22 +1,22 @@
+class ModuleTester
+  include GitisAccess
+end
+
+class CachedModuleTester
+  include GitisAccess
+  self.use_gitis_cache = true
+end
+
 describe GitisAccess do
   let(:factory) { Bookings::Gitis::Factory }
   before { allow(factory).to receive(:crm) { true } }
 
   context 'without configuring caching' do
-    class ModuleTester
-      include GitisAccess
-    end
-
     subject! { ModuleTester.new.gitis_crm }
     it { expect(factory).to have_received(:crm).with(read_from_cache: false) }
   end
 
   context 'without configuring caching' do
-    class CachedModuleTester
-      include GitisAccess
-      self.use_gitis_cache = true
-    end
-
     subject! { CachedModuleTester.new.gitis_crm }
     it { expect(factory).to have_received(:crm).with(read_from_cache: true) }
   end
diff --git a/spec/forms/schools/on_boarding/experience_outline_spec.rb b/spec/forms/schools/on_boarding/experience_outline_spec.rb
index 4f5b65b5c1..c1c221f510 100644
--- a/spec/forms/schools/on_boarding/experience_outline_spec.rb
+++ b/spec/forms/schools/on_boarding/experience_outline_spec.rb
@@ -16,14 +16,14 @@
       it { is_expected.to validate_presence_of :teacher_training_details }
 
       context 'when teacher_training_url is present' do
-        INVALID_URLS = ['javascript:alert("oh no!")//http://example.com'].freeze
-        VALID_URLS = ['https://www.example.com', 'http://example.com'].freeze
+        invalid_urls = ['javascript:alert("oh no!")//http://example.com'].freeze
+        valid_urls = ['https://www.example.com', 'http://example.com'].freeze
 
-        INVALID_URLS.each do |url|
+        invalid_urls.each do |url|
           it { is_expected.not_to allow_value(url).for :teacher_training_url }
         end
 
-        VALID_URLS.each do |url|
+        valid_urls.each do |url|
           it { is_expected.to allow_value(url).for :teacher_training_url }
         end
       end
diff --git a/spec/lib/notify/notify_sync_spec.rb b/spec/lib/notify/notify_sync_spec.rb
index 89e982c98f..e70ff6299b 100644
--- a/spec/lib/notify/notify_sync_spec.rb
+++ b/spec/lib/notify/notify_sync_spec.rb
@@ -52,7 +52,7 @@
       after { subject.compare }
 
       specify "should state that exact templates match" do
-        expect(STDOUT).to receive(:puts).with(
+        expect($stdout).to receive(:puts).with(
           [
             matching_template_id.ljust(18),
             matching_template_name.ljust(40),
@@ -79,7 +79,7 @@
       after { subject.compare }
 
       specify "should state that local-only templates are missing from remote repository" do
-        expect(STDOUT).to receive(:puts).with(
+        expect($stdout).to receive(:puts).with(
           [
             local_only_template_id.ljust(18),
             "Unknown".ljust(40),
@@ -111,7 +111,7 @@
       after { subject.compare }
 
       specify "should state that local-only templates are missing from local repository" do
-        expect(STDOUT).to receive(:puts).with(
+        expect($stdout).to receive(:puts).with(
           [
             remote_only_template_id.ljust(18),
             remote_only_template_name.ljust(40),
diff --git a/spec/models/bookings/data/school_mass_importer_spec.rb b/spec/models/bookings/data/school_mass_importer_spec.rb
index fe4488f914..a392886d1b 100644
--- a/spec/models/bookings/data/school_mass_importer_spec.rb
+++ b/spec/models/bookings/data/school_mass_importer_spec.rb
@@ -3,7 +3,7 @@
 
 describe Bookings::Data::SchoolMassImporter do
   before do
-    allow(STDOUT).to receive(:puts).and_return(true)
+    allow($stdout).to receive(:puts).and_return(true)
     allow_any_instance_of(Kernel).to receive(:print).and_return(nil)
   end
 
@@ -36,7 +36,7 @@
       let(:school_type_id) { 2 }
 
       before do
-        # note these values are present in spec/sample_data/edubase.csv
+        # NOTE: these values are present in spec/sample_data/edubase.csv
         {
           1 => 'Early years',
           2 => 'Primary (4 to 11)',
diff --git a/spec/models/concerns/yaml_model_spec.rb b/spec/models/concerns/yaml_model_spec.rb
index 1fe707eaa3..792c15fd9a 100644
--- a/spec/models/concerns/yaml_model_spec.rb
+++ b/spec/models/concerns/yaml_model_spec.rb
@@ -1,13 +1,14 @@
 require 'rails_helper'
-describe YamlModel, type: :model do
-  class YamlTestModel
-    include YamlModel
 
-    id_attribute :dob, :date
-    attribute :firstname, :string
-    attribute :lastname, :string
-  end
+class YamlTestModel
+  include YamlModel
 
+  id_attribute :dob, :date
+  attribute :firstname, :string
+  attribute :lastname, :string
+end
+
+describe YamlModel, type: :model do
   let(:described_class) { YamlTestModel }
 
   describe '.data_path' do
diff --git a/spec/models/feature_spec.rb b/spec/models/feature_spec.rb
index 3707b12b78..464762cd42 100644
--- a/spec/models/feature_spec.rb
+++ b/spec/models/feature_spec.rb
@@ -1,12 +1,12 @@
 require 'rails_helper'
 
-describe Feature do
-  class Tester
-    def self.hello
-      'world'
-    end
+class Tester
+  def self.hello
+    'world'
   end
+end
 
+describe Feature do
   before { Feature.instance.current_phase = 10 }
   after { Feature.instance.current_phase = nil }
   subject { Feature.instance }
diff --git a/spec/notify/notify_spec.rb b/spec/notify/notify_spec.rb
index 84d975af88..b4ed0ae975 100644
--- a/spec/notify/notify_spec.rb
+++ b/spec/notify/notify_spec.rb
@@ -2,6 +2,25 @@
 require Rails.root.join('spec', 'support', 'notify_fake_client')
 require Rails.root.join('spec', 'support', 'notify_retryable_erroring_client')
 
+class StubNotification < Notify
+  attr_accessor :name
+
+  def initialize(to:, name:)
+    self.name = name
+    super(to: to)
+  end
+
+private
+
+  def template_id
+    'ec830a0d-d032-4d4b-a107-xxxxyyyyzzzz'
+  end
+
+  def personalisation
+    { name: name }
+  end
+end
+
 describe Notify do
   include ActiveJob::TestHelper
   let(:to) { 'somename@somecompany.org' }
@@ -53,25 +72,6 @@
   end
 
   describe 'custom notify_client' do
-    class StubNotification < Notify
-      attr_accessor :name
-
-      def initialize(to:, name:)
-        self.name = name
-        super(to: to)
-      end
-
-    private
-
-      def template_id
-        'ec830a0d-d032-4d4b-a107-xxxxyyyyzzzz'
-      end
-
-      def personalisation
-        { name: name }
-      end
-    end
-
     let :recipients do
       %w[test1@user.com test2@user.com]
     end
diff --git a/spec/services/bookings/gitis/entity_spec.rb b/spec/services/bookings/gitis/entity_spec.rb
index 3c8574334a..35ad87502e 100644
--- a/spec/services/bookings/gitis/entity_spec.rb
+++ b/spec/services/bookings/gitis/entity_spec.rb
@@ -1,5 +1,24 @@
 require 'rails_helper'
 
+class Associated
+  include Bookings::Gitis::Entity
+
+  entity_id_attribute :associatedid
+  entity_attribute :description
+  entity_association :testassoc, TestEntity
+end
+
+class TestInternal < TestEntity
+  entity_attribute :hidden, internal: true
+end
+
+class TeamEntity
+  include Bookings::Gitis::Entity
+
+  entity_attribute :name
+  entity_collection :players, TestEntity
+end
+
 RSpec.describe Bookings::Gitis::Entity do
   include_context 'test entity'
 
@@ -212,10 +231,6 @@
   end
 
   describe "private attributes" do
-    class TestInternal < TestEntity
-      entity_attribute :hidden, internal: true
-    end
-
     it { expect(TestInternal.select_attribute_names).to include('hidden') }
     it { expect(TestInternal.respond_to?('hidden')).to be false }
     it { expect(TestInternal.respond_to?('hidden=')).to be false }
@@ -238,14 +253,6 @@ class TestInternal < TestEntity
       TestEntity.new('testentityid' => SecureRandom.uuid, 'firstname' => 'test')
     end
 
-    class Associated
-      include Bookings::Gitis::Entity
-
-      entity_id_attribute :associatedid
-      entity_attribute :description
-      entity_association :testassoc, TestEntity
-    end
-
     context 'with new instance' do
       subject { Associated.new('description' => 'test') }
 
@@ -380,13 +387,6 @@ class Associated
   end
 
   describe '.entity_collection' do
-    class TeamEntity
-      include Bookings::Gitis::Entity
-
-      entity_attribute :name
-      entity_collection :players, TestEntity
-    end
-
     context 'initializing with data' do
       let(:player1) { SecureRandom.uuid }
       let(:player2) { SecureRandom.uuid }
diff --git a/spec/services/bookings/gitis/factory_spec.rb b/spec/services/bookings/gitis/factory_spec.rb
index 16c2d6504c..a35d512de8 100644
--- a/spec/services/bookings/gitis/factory_spec.rb
+++ b/spec/services/bookings/gitis/factory_spec.rb
@@ -35,12 +35,12 @@
     before { allow(factory).to receive(:token).and_return('a.fake.token') }
 
     context 'with read_from_cache' do
-      subject! { factory.caching_store(true) }
+      subject! { factory.caching_store(read_from_cache: true) }
       it { is_expected.to be_kind_of Bookings::Gitis::Store::ReadWriteCache }
     end
 
     context 'without read_from_cache' do
-      subject! { factory.caching_store(false) }
+      subject! { factory.caching_store(read_from_cache: false) }
       it { is_expected.to be_kind_of Bookings::Gitis::Store::WriteOnlyCache }
     end
   end
diff --git a/spec/services/bookings/gitis/store/read_write_cache_spec.rb b/spec/services/bookings/gitis/store/read_write_cache_spec.rb
index 2ad1ee9efb..ad015d35e5 100644
--- a/spec/services/bookings/gitis/store/read_write_cache_spec.rb
+++ b/spec/services/bookings/gitis/store/read_write_cache_spec.rb
@@ -1,12 +1,12 @@
 require 'rails_helper'
 
-describe Bookings::Gitis::Store::ReadWriteCache do
-  class Person
-    include Bookings::Gitis::Entity
-    entity_id_attribute :personid
-    entity_attribute :fullname
-  end
+class Person
+  include Bookings::Gitis::Entity
+  entity_id_attribute :personid
+  entity_attribute :fullname
+end
 
+describe Bookings::Gitis::Store::ReadWriteCache do
   let(:version) { 'v1' }
   let(:dynamics) { Bookings::Gitis::Store::Dynamics.new 'a.fake.token' }
   let(:cache) { Rails.cache }
diff --git a/spec/services/bookings/gitis/store/write_only_cache_spec.rb b/spec/services/bookings/gitis/store/write_only_cache_spec.rb
index bdae3bc57a..c5c47967cd 100644
--- a/spec/services/bookings/gitis/store/write_only_cache_spec.rb
+++ b/spec/services/bookings/gitis/store/write_only_cache_spec.rb
@@ -1,12 +1,12 @@
 require 'rails_helper'
 
-describe Bookings::Gitis::Store::WriteOnlyCache do
-  class Person
-    include Bookings::Gitis::Entity
-    entity_id_attribute :personid
-    entity_attribute :fullname
-  end
+class Person
+  include Bookings::Gitis::Entity
+  entity_id_attribute :personid
+  entity_attribute :fullname
+end
 
+describe Bookings::Gitis::Store::WriteOnlyCache do
   let(:version) { 'v1' }
   let(:ttl) { 1.hour }
   let(:cache) { Rails.cache }
diff --git a/spec/services/candidates/registrations/contact_information_spec.rb b/spec/services/candidates/registrations/contact_information_spec.rb
index f8e085364f..1d065828e5 100644
--- a/spec/services/candidates/registrations/contact_information_spec.rb
+++ b/spec/services/candidates/registrations/contact_information_spec.rb
@@ -53,12 +53,12 @@
       it { is_expected.to validate_length_of(:phone).is_at_most(50).with_message(too_long_msg) }
 
       context 'phone is present' do
-        VALID_NUMBERS = ['01434 634996', '+441434634996', '01234567890'].freeze
-        INVALID_NUMBERS = ['7', 'q', '+4414346349'].freeze
-        BLANK_NUMBERS = ['', ' ', '   '].freeze
+        valid_numbers = ['01434 634996', '+441434634996', '01234567890'].freeze
+        invalid_numbers = ['7', 'q', '+4414346349'].freeze
+        blank_numbers = ['', ' ', '   '].freeze
 
         context 'valid numbers' do
-          VALID_NUMBERS.each do |number|
+          valid_numbers.each do |number|
             subject { described_class.new phone: number }
             before { subject.validate }
 
@@ -69,7 +69,7 @@
         end
 
         context 'invalid numbers' do
-          INVALID_NUMBERS.each do |number|
+          invalid_numbers.each do |number|
             subject { described_class.new phone: number }
             before { subject.validate }
 
@@ -80,7 +80,7 @@
         end
 
         context 'blank number' do
-          BLANK_NUMBERS.each do |number|
+          blank_numbers.each do |number|
             subject { described_class.new phone: number }
             before { subject.validate }
 
@@ -96,7 +96,7 @@
       let(:too_long_msg) { 'Postcode must be 20 characters or fewer' }
       it { is_expected.to validate_length_of(:postcode).is_at_most(20).with_message(too_long_msg) }
 
-      VALID_POSTCODES = [
+      valid_postcodes = [
         'DN55 1PT',
         'CR2 6XH',
         'B33 8TH',
@@ -106,17 +106,17 @@
         'ch63 7ns'
       ].freeze
 
-      INVALID_POSTCODES = [
+      invalid_postcodes = [
         'horses',
         'N0T AP057C0D3',
         'B3333 1BB',
         'CH3',
       ].freeze
 
-      BLANK_POSTCODES = ['', ' ', '  '].freeze
+      blank_postcodes = ['', ' ', '  '].freeze
 
       context 'valid postcodes' do
-        VALID_POSTCODES.each do |postcode|
+        valid_postcodes.each do |postcode|
           subject { described_class.new postcode: postcode }
           before { subject.validate }
 
@@ -127,7 +127,7 @@
       end
 
       context 'invalid postcodes' do
-        INVALID_POSTCODES.each do |postcode|
+        invalid_postcodes.each do |postcode|
           subject { described_class.new postcode: postcode }
           before { subject.validate }
 
@@ -138,7 +138,7 @@
       end
 
       context 'blank postcodes' do
-        BLANK_POSTCODES.each do |postcode|
+        blank_postcodes.each do |postcode|
           subject { described_class.new postcode: postcode }
           before { subject.validate }
 
diff --git a/spec/services/candidates/registrations/registration_as_placement_request_spec.rb b/spec/services/candidates/registrations/registration_as_placement_request_spec.rb
index 2e3253eb34..5a506dac06 100644
--- a/spec/services/candidates/registrations/registration_as_placement_request_spec.rb
+++ b/spec/services/candidates/registrations/registration_as_placement_request_spec.rb
@@ -4,7 +4,7 @@
   let(:urn) { 11_048 }
   subject { described_class.new session }
 
-  PII = {
+  pii = {
     "full_name" => 'Testy McTest',
     "email" => 'test@example.com',
     "building" => "Test building",
@@ -41,7 +41,7 @@
 
       context 'PII' do
         # Redundant given the next spec, but going for clarity!
-        PII.each do |k, _|
+        pii.each do |k, _|
           it "removes #{k}" do
             expect(subject.attributes[k]).to eq nil
           end
@@ -90,7 +90,7 @@
 
       context 'PII' do
         # Redundant given the next spec, but going for clarity!
-        PII.each do |k, _|
+        pii.each do |k, _|
           it "removes #{k}" do
             expect(subject.attributes[k]).to eq nil
           end
diff --git a/spec/services/schools/dfe_sign_in_api/client_spec.rb b/spec/services/schools/dfe_sign_in_api/client_spec.rb
index c155849ccb..256a7d3e45 100644
--- a/spec/services/schools/dfe_sign_in_api/client_spec.rb
+++ b/spec/services/schools/dfe_sign_in_api/client_spec.rb
@@ -1,5 +1,19 @@
 require 'rails_helper'
 
+class TestAPI < Schools::DFESignInAPI::Client
+  def data
+    response
+  end
+
+private
+
+  def endpoint
+    URI::HTTPS.build \
+      host: "some-test-api-host.signin.education.gov.uk",
+      path: '/testapi'
+  end
+end
+
 describe Schools::DFESignInAPI::Client do
   describe '.enabled?' do
     context 'when setting is on and all required environment variables are present' do
@@ -95,20 +109,6 @@
         receive(:enabled?).and_return true
     end
 
-    class TestAPI < Schools::DFESignInAPI::Client
-      def data
-        response
-      end
-
-    private
-
-      def endpoint
-        URI::HTTPS.build \
-          host: "some-test-api-host.signin.education.gov.uk",
-          path: '/testapi'
-      end
-    end
-
     subject { TestAPI.new.data }
 
     {
diff --git a/spec/support/rate_limiting_support.rb b/spec/support/rate_limiting_support.rb
index c516366389..8eca127724 100644
--- a/spec/support/rate_limiting_support.rb
+++ b/spec/support/rate_limiting_support.rb
@@ -1,6 +1,6 @@
-include ActiveSupport::Testing::TimeHelpers
-
 shared_examples "an IP-based rate limited endpoint" do |desc, limit, period|
+  include ActiveSupport::Testing::TimeHelpers
+
   describe desc do
     let(:memory_store) { ActiveSupport::Cache.lookup_store(:memory_store) }
 
diff --git a/spec/validators/email_format_validator_spec.rb b/spec/validators/email_format_validator_spec.rb
index 06d4e9b9c5..48cb3c699a 100644
--- a/spec/validators/email_format_validator_spec.rb
+++ b/spec/validators/email_format_validator_spec.rb
@@ -1,12 +1,13 @@
 require 'rails_helper'
 
-describe EmailFormatValidator do
-  class TestModel
-    include ActiveModel::Model
-    attr_accessor :email_address
-    validates :email_address, email_format: true
-  end
+class TestModel
+  include ActiveModel::Model
+  attr_accessor :email_address
 
+  validates :email_address, email_format: true
+end
+
+describe EmailFormatValidator do
   before { instance.valid? }
   subject { instance.errors.to_hash }