This is what I would do......
Get class 1 medical
Get the PPL while still working, go to the USA and do an intensive course. 4 weeks should cover it. (if you don't have one already)
Get the JAA ground exams, while still working.
Once you have those (or during), quit your job, go to the USA and do and intensive FAA IR / CPL course. Forget JAA in the US courses.......10 weeks should do it
Come back and convert CPL and IR to JAA.
You'll save in the order of £20,000 if you do it right, you can have your JAA fATPL by this time next year, you will hold FAA CPL/IR (ME) in addition.
300 hrs + 50 ME time cost me around $30,000. Add in the JAA exams and conversion, say £10, 000, the whole shebang could be done for ~£30,000....
Good luck