There is a big chunk of the CPL/IR that can be done while you are still in work and earning. You could continue to work, pass your ppl, start distance learning and pass the exams, (which you wont find hard with an aero eng background) and do all the hour building all without leaving work.
The face the decision of whether you want to leave work/take some time off for the CPL and IR. In the mean time, you are earning a decent amount of cash, and not getting into more debt. If you can save up a fair wedge towards the CPL/IR, then you will have a better change of persuading your frieldly bank manager to lend you some cash....
NB