Have you got any work experience in medicine? Or are you saying you want to do medicine based on a fantasy of doctors being highly paid, respected people? Grad med is incredibly competitive. You'd be looking at possibly 40 applicants per place. How much do you know about the career structure in medicine? MMC/MTAS? I would not say that being a doctor was a respected profession, in terms of the lack of thanks, the bitchiness of multidisciplinary co-operation, and the litigious situation you'd find yourself in if you do something wrong.
Would you be prepared to sit GAMSAT/BMAT/UKCAT? Have you done voluntary work long-term to demonstrate a commitment to the healthcare profession and an insight into the views of the patient? Have you spoken to doctors about how they feel about their jobs? Currently a lot of them are looking at not having a job in a few weeks. How's that for job security? Could you cope with 7 years at uni (mentally and financially)? Currently, GEP Med is funded by the NHS for years 2-4, but this will end soon.
You could do a lot with a BioMed degree; working as an NHS Biomedical Scientist, do research work, or work in other sectors that don't mind what subject your degree is in. I don't agree with what Sammi22's friend says (not saying you're wrong, I just don't agree) about being more employable due to having two relevant degrees. A biomedical science degree is worth nothing once you have a medical degree, because it supplies no additional knowledge to what is covered in the pre-clinical years. The hospital sponsor thing is almost unheard of; there are plenty of doctors to go around, they don't need to pay out to keep them there. And F1's get free accomodation at their hospital anyway.