Medicine as a second undergraduate degree, you're able to get maintenance loan. So It's just a matter of forking up 9k tuition each year. If you work your butt off you can do it yourself. You can also find bursaries through Uni (certain students who meet criteria can get yearly bursaries of up to 1.5k is the most I've seen from some uni's) or other places.
I know of people who are currently funding themselves these ways. It does mean working before or alongside a challenging degree and maybe even having family help out for a few thousand. But it is entirely possible even more so than even getting into med school lol