I don't think the CTC requirements are particularly 'over the top'
Unfortunately as you said, they can be picky. If your GCSE grades especially Science & Maths were not exactly the best then thats more then likely your problem and believe it or not my problem and many others aswell.
Unfortunately I got a D at GCSE science and I need to re-sit GCSE Physics in order to get a C which is the required grade. Bare in my I have A-levels, AS-levels and a 2:1 Hons Computer Science degree, so I know were you are coming from.
My only choice is to resit the GCSE which I am in the process of doing now.
Best case is to just do what is required, don't moan and get it done.