you may struggle to get on a sponsorship..not onylb ecause they're a rare thing to come across nowadays but if you find one they usually ask for a-levels. Not sure what the qualification you have in maths is, but a good knowledge of maths will be very usefull throughout all your training and your career. If you choose a modular/integrated route through a flying organisation, you should be fine with just your GCSE's...but some may require you to sit basic maths and physics tests.
A diploma would be good, even if it is of no relevance to the flying, atleast it's something to fall back on if you need to.
The hours you've got won't make a difference in getting into any flying colleges or what not...but you've already got some experience flying which will credit towards your PPL....which is always good to have.
I don't know if what i've wrote helps you at all, lol. Sorry if not.
Mark