Hi ILS30LGB,
Are you returning to the UK within the next year or so? If not then there is at least one ATPL Written course provider based in Florida. They conduct full time residential and distance learning courses. The exams are taken up in Orlando.
As for "best" school in the UK, you'll probably get all sorts of recommendations from people on pprune, but the "best" is the school (or schools) that suits you and your needs.
Personally for the flight training I'm going to use either Aeros or Bristol Flying Centre and ground school, well since the flight training exhibition at LHR on Saturday, I'm torn between Bristol Ground School and London Metropolitan University (Distance Learning for me as I can't afford to take the time off work).
If anyone is thinking "why is he replying at 2am in the morning?", well I'm on night shift and pprune is one way of getting me through the night without falling asle.......
Best wishes,
Charlie Zulu.