Regarding considering to apply to Oxbridge (well the advice goes for all your choices really), go there, meet the lectuers/students, find out what it'll be like to study there, exactly what it is on the course. Try doing some aspects of the course if possible. If you really love it, then definitely go for it even if you don't have absolutely amazing Edit: UMS marks/ Bmat.
It was only yesterday whilst I was at an interview at another university that I realised what a right choice I'd made applying to Cam. As I prefered the course and style of teaching above all else. even taking into consideration the lack of clinical experience.