At the sixth form centre I'm planning on attending next September, they're running both AQA Biology and AQA Human Biology. I want to study Medicine at university (taking Chemistry, Maths and Psychology also), so does it matter which Biology course I do and do universities have any preference?
Human biology may be better for you in the sense that you already know you're interested in the subject, while biology is rather more varied and as such there are some things you like more than others. Literally everywhere I've looked at treated biology and human biology as interchangeable (this is for (bio)medical science, which tends to have similar requirements to medicine). Chemistry is definitely the most important subject for medics, though.
i was at a medicine talk at UCLl ast year and they said they preferred biology over human bio. if you go on the cambridge list of good and bad ("academic" and "less academic") subjects, human bio is listed as "less acdemic".
Do Biology - as has been said it's considered a more academic subject. It will also give you a better grounding. Don't worry if there'd be a few extra medical details in the human biology course - there's plenty of time to learn those at medical school, and it won't be significant anyway.