Hi Skint.....
Just one thought..if you go to the US to train and then intend to hour build then you need to consider the visa requirements.
To work out there you obviously need the authorisation, which is going to be the J-1 visa. To be eligible for this you must have only the very basic of flying hours, any more than about 70hrs and you'll struggle.
So if you are going to build hours then my advice would be to go out to the US, do your FAA CPL/IR and instructor ratings with a good school that can issue the J-1, then stay and work for a couple of years, come back with an FAA ATP and then do your JAA conversion. You never know you may even have a really great time while you're out there ( I know I did..!! )
all the best,
Captmav