Total not updating when switching between card payment and pay later

[duncan-s-white]

I am experiencing an issue where the total does not update when I switch between the card payment option and the pay later option.
The message associated is displayed and hidden correctly, but the total price does not remove the fee when the pay later option is selected. However when you proceed the correct amount is passed through to the confirmation page
This happens whether the price set is radio buttons or select input.
This extension is exactly what we need, so I could be interested in helping fix it, if I can.
I include 2 screenshots