Despite the popular belief to the contrary, you *can* use an FAA PPL to take a G-registered aircraft out of the UK. It is perfectly legal, read the ANO regarding licences rendered valid. I have done so on several occasions.
Be prepared to put up with the negative feelings many British schools have towards US-taught pilots. You will also find flying in the USA more fun and hassle-free and will want to go back there for flying holidays
