B.G.
if you have a green card, u dont need foreign cetificates.
the green card is a permanent residence, the next step is the passport. you should not say you are british but a futur yankee!
The US doesnt really care of your british licenses!
the best way is to go to the US under a B2 visa and go talk directly to the FSDO, ask the chief manager, not the secretary!
they will issue you a FAA validation at no cost...forget this CAA form, it s just a scam !
I know what I am talking about, I have a long experience with the yankees, post and pre 9/11