First year abroad medicine and then transfer back to uk for rest?

I'm not aware of any UK med school which would consider this.

UK medical schools don't accept transfers outside of existing schemes (which are as far as I'm aware, Oxford -> London medical schools and St Andrews preclinical -> clinical partner medical schools), and they also don't accept students who have previously started but not completed a medical degree for any reason anywhere else. This is stated on every medical school admissions webpage that I am aware of.

You can do your medical degree abroad then work in the UK as a doctor - but that is a very different prospect.

The only other way to study in the UK and abroad on a single medical degree is through an existing scheme (I think QMUL has one with Malta and Southampton has one with Germany) or by doing an elective abroad (which I gather is fairly common, but this may just be for a few weeks or a month or two).