Some unis will want maths, others won't. Have a look at what entry requirements the unis you're interested in want.
My friend got into medicine with bio, chem, maths and food tech.
Another got into dentistry with bio, chem and good tech. She dropped maths after AS.
Another medic in my school did bio, chem and maths.
And a third medic I know of did bio, chem and psychology.
I'd say, as long as you have bio and chem, you're good to go!