The current requirement has been in place since 2017. Parts of it apply to flying N-reg on a full FAA licence as well as G-reg. It stopped us renting to FAA pilots because the process takes longer than they normally visit for. How do I know it applies to N-reg (apart from the requirement)? An FAA holder came to me for English language assessment before going to Gatwick to submit the form(s) as demanded by the CAA. He had an N-reg aircraft in the UK. It's actually more straight forward to fly an N-reg in the UK on a British licence. Here's the current version of the I.N. :-
http://publicapps.caa.co.uk/docs/33/...ice2017029.pdf