Another thing to note is that FAA instructors don't teach, they have never been trained to teach like a UK instructor and don't demonstrate much either. Briefings are minimal and despite all they say, they do not follow the JAA or AOPA syllabus. (If you don't believe me, just take a syllabus with you and check it off as you go)
As well as doing the groundschool, you might find a few lessons in UK a good idea, then you would see the difference earlier rather than later.