If 'you have heard that Britain is desperate for doctors' and that is the sort of level of research you have done, I'd consider a few points.
1) Medicine isn't just a proffesion its a vocation.
2) The UK currently has more doctors than jobs (however that doesn't mean it doesn't need more, there just isn't the funding)
3) Medicine, is one of the toughest courses to get on. Having a minimum of AAB at A-level is just a small part of being considered for interview.
4) Medical schools look favourably on mature students in some cases, you would have to convince them of your dedication and commitment to a very difficult vocation.
5) Given that there are usually more than 10 applicants per place for medical school (all usually with AAB or better at A-level) there isn't any reason to provide funding for the course.
6) You would probably be able to get a student loan, and there are bursaries and funds from benefactors you could apply for, but to the best of my knowledge no actual assistance from the government for the reasons stated above.
7) Being in your 30s does not preclude you from a career in medicine, but not doing you research will.