Commiserations. I know of a few people who have got in to Hill colleges to do things like combined social sciences. The problem is I'm not sure they would ever let you change to a subject like law, which is normally over-subscribed anyway. My advice would be to get A levels and then reapply. I know of several people who have got into Oxbridge doing this, despite previous rejections. Having your grades makes it much easier for a department to make a decision since you're a known quantity.