Thanks for all the replies folks, think I've sussed it, think the 6 year course is the way to go, requirements like 5 A*-C and 3 A Level (BBC), and I'd just have to work for another year at it. Gonna stick with psychology because I'd rather do something I enjoy and get great results than a sucky maths grade because I hate the subject.
2 years a levels, 6 years at a medschool (hopefully) and I'll see you all in 8 years :P Composing a list now of all the schools I meet the requirements for at GCSE, anyone know where I can get a list of the 6 year courses?
Thanks again for all the comments, been enlightening.