hello, M79,
You probably posted in this forum because you want to go on to a JAA CPL/IR? If this is so, then all you need is an FAA PPL, not JAA, which can be done in many places in the US for less money and in under 21 days. If you really want to be sure, you can get the book in the UK, even do the ground exam in the UK, as well as the medical, but all should be possible well within the 21 days in the US too.
Bear in mind that you loose a JAA PPL when you do a higher JAR licence, the FAA is there to keep (even without any more testing ever).
You may have to study a bit more for the JAA exams, but nobody stops you from doing that if you do the FAA PPL.
cheers IP