Myself, I would go the conversion route. A lot of people poo-poo this route, but I think if people are clever you can go from 0 to ATPL for less than £30k.
In fact one European FTO (I won't publish their name here as I'd probably be in breach of PPRuNe advertising rules
) are advertising for Interns if you are prepared to live and work in California (who wouldn't?) for a couple of years. Their website claims that the course from 0 to FAA CPL/IR CFI CFII MEI including JAA PPL in the UK is £29,900. After you have completed this you work for them, paid, while building your hours, they provide accomodation etc. At the same time you do the ATPL ground exams via distance learning, and take the writtens in the UK. Once you have 1500hrs they will provide a conversion course for the Intern in the UK.
So all being well, for £29,900 you walk away after 2 years with FAA ATP, JAA ATPL, and 1500 hrs, and probably a substantial amount of ME time. Can't be bad can it?