I don't think I'll be wanting to hand over 45k for an atpl making it something stupid like 70k total inc flight hours, do you have any idea how much just a CPL+IR+PPL would cost? Thanks for the reply!
Both the CPL and IR will have a theory side plus exams, You'll study the CPL theory + exams and then 6 months later you study the IR theory + exams.
When you eventually decide you're good enough for the airlines you'll need to do the 14 ATPL exams which are much the same as the CPL & IR theory. So in a sense you'll be paying for your professional theory twice.
So:
PPL > CPL(+theory) + IR (+theory) + FI(r)
or
PPL + ATPL then > CPL (practical only) + IR (practical only) + FI(r)
Unfortunately becoming an instructor is going to cost you a huge amount of your hard earned cash. And take a look at the pay you'll be on (£10k to £15k pa) so if your taking home about £1k a month you don't want any loans to pay off either.
So self funding is the best way to achieve this route. If you're only 14 you have plenty of time to save £70k 
If you can get into the RAF and have your training paid for by the tax payers then that's the best route to take IMHO.