Hi Little flyer,
I think many people will tell you physics is required as most cadet schemes will want you to have it, but if you want a fun career in flying you can work up on your own, and get the CPL, or ATP without going as a cadet, try Africa or somewhere else exciting to get experience, then when you are ready to settle down to a cozy airline job you will have so much experience as a pilot no one is going to care what GCSE you did.
As far as I can recall you do not need any GCSE or A levels to do the CPL and ATPL, just the brains to pass the exams.
Good luck with your career
Crash