For the moment I would keep your full time job and salary. I would find a localish flying school and get a PPL. I would then build a few hours perhaps by spending a fortnight in the USA on holiday.
Then its ATPL Groundschool time via distance learning modualar course.
By the time you have all that sorted it will be about two years hence and the market will have improved sufficiently to allow you to sensibly spend £30,000 getting in and throwing away your current job.
Quitting now to go immediately onto an integrated course seems over opitmistic to me.
Good luck,
WWW