Yes you can and I did - I was rejected though. So now I have my 4 med choices and I reckon I've only got a small chance with one of those, so I'm in dire need of a life re-think. Hehe, I do sympathise, this is my second time round at UCAS applications and it doesn't get easier!
ahh, I'm sure you'll be fine, good luck with your application. Sorry I can't be of much help, but I think you can find figures about clearing online, gives an idea of what places are available.