For medicine, the subjects which will give you the most options of unis will be biology and chemistry. Taking one will mean you still have options but not so many.
For finance degrees, the subjects which unis will require or recommend are maths and further maths (especially for top unis).
Your options currently would mean you’d have some options in both fields but you would be limited by the lack of chem in med and for some top unis the lack of fm for finance.
My advice would be to explore your interests once your exams are over and see what suits you. I was undecided between whether i was more interested in astrophysics or zoology type degrees during year 11 but i explored both fields through documentaries, online courses etc and this clarified to me that i would like to go toward the zoology side of things so i switched my original idea of taking double maths, physics and biology to maths, biology and im also thinking environmental science and epq which ill start next year.
As i take maths and biology, id be happy to answer questions about those if you need 🙂