if you strike lottery and pay full fees for overseas education, i think some uk or australia school will take you.

if they dont feel that your poly diploma is sufficient for entry, then you can do a degree first in life science. then followed by grad school.

alternatively, you can also choose to sit a levels as private candidate, then with a good a level results, apply for undergraduate school, then graduate medical school.
whole process may take 12 or 13 years.

but if you are determined. im sure by 55 years, you should be able to graduate with a post grad mbbs/md.

bottomline is if you have the $$$~1million cash and intellect and drive to study, it is doable!

give your family 200k for their expenses. then for the rest of 800k, keep it for your a level, degree and post grad use.