Couple of things that might make your decision easier. The OAT/Jerez integrated courses aren't £50k I am afraid, likely closer to £100k (and excluding living costs). Modular will depend on a number of factors including where you go (US or UK or some other far flung place). Expect to not get much change from £50k though and not much more than 250 hours at the end of it. Of course that will be the fatpl only (PPL, ME, CPL, IR, MCC).A type rating can add on another 10-25k depending on aircraft should you decide to go down that path but that is a few years away so leave the decision on that for another day and who knows what the market will hold for us all in the next few years in anycase.
I am pretty sure I read somewhere that the likes of HSBC etc aren't providing professional studies loans anymore. Perhaps OATS, Jerez, Cabair etc have relationships with local banks that can get you the finance required, however, I am pretty sure if going modular that finance has all but dried up unless of course the security you can offer on your folks house swings the bank manager.
I think it is fair to say that if getting into the RHS of a jet with a major airline and less than 250 hours under your belt sets your world on fire then go integrated, assuming you can fund it. BUT and a big BUT, you might never get picked up by one of the airlines. In order to maximise your chances you will need:-
- high passes in the ATPL ground school subjects
- first time passes on the flying side within minimum of time
- a decent personality
- get along with everybody - students and instructors/management
- don't fall out with the instructors who will constantly be assessing you and will of course be the ones who recommend you to the airlines
- be in the right place at the right time. Unfortunately if you finish and no one is hiring then you might miss out purely because you aren't at school the day that Mr BA knocks on the door asking for 10 cadets. That is the way the cookie crumbles I am afraid.
Having done all of that you still need to pass any sim ride, interviews entrance exams, group workshops or psychometric tests that the airlines require of you.
If you are pretty confident that you can do all of the above then go for it. If your not sure then you might just want to save yourself some cash and go modular. There are a lot of ex integrated students that never made it into an airline for whatever reason - more likely bad timing if nothing else. Of course OAT etc won't tell you that in their marketing spin.
Finally, the fatpl won't expire so long as get your IR within the prescribed time and don't let it get to far out of date. You would be foolish to let it lapse in anycase as it doesn't take much rocket science to work out that a pilot who is current on type with a valid IR is much likelier to pass a sim ride than someone who has gone back to work and let it all slip. LASORS (do a search) has all the rules and regs on what you need to get and how long everything stays current.
Good luck.