Firstly, with medicine, the reputation of the university is less important as all medical degrees are very similar in quality.
Secondly, with medicine, I think most universities only look at your first 8/9 gcses as not everyone has the chance to take more. They always look at maths, english and science grades, so if your a*s are in these your application will be stronger. They give each grade a certain number (say 10 for an a*, 8 for an a etc) and then calculate a total, which they use to compare candidates.
Thirdly, very few people get A*A*A*A at a level, particularly if you've only got 3 a*s at gcse.