First of all, forget the sensationalism generated by the gutter press. Throughout my 38 years in the RAF as a pilot, I did not encounter racism at all, and I served with a number of races of all ranks [the latest a Pakistani SAC, about 3 years ago].
The latest appointments list in the press shows an Air Commodore posted to MOD - he's Jamaican and a fast jet QFI; race has no bearing - ability does.
Finally, get back into the ATC. OASC sets great store on evidence of motivation, and there is no greater evidence than membership of that organisation. You should be able to organise your life to allow you to attend most drill nights as well as earning part time - thousands of us have done it in the past. You may have to sacrifice some of your social life, but the rewards long term outweigh the short term. Besides, it's another example of motivation where you can show the Board that you have prioritised your time to fulfill your life-long ambition to fly in the Royal Air Force.
Joining the RAF should be an almost obsessive focus in your life next to achieving the best academic qualifications you can possible work for.
Bust a gut - you have a lot of hard work ahead of you, but when you get there you will realise that it was all worth it in the end - especially when you are looking at a target through the Typhoon HUD!