My son has the same issues. I contacted Stoke and Manchester Met which are considered to be two of the best universities in game design and was told it goes on on a UCAS points system and interview but all subjects are valid. My son will only get a c in maths so will not take this option but had selected computer science, History and English language. He may also do an AS in photography. It seems if you have relevant interests and possible one of the desired subjects makes sense, and you make the grade then all good. It maybe different if your course is a programming heavy type degree as apprised to one of the more design/developer types.