Hi,
Maybe I can help here. My son is currently 3rd year student of Biochemistry at Oxford.
He said that you don't need maths to apply for Biochem. However, everyone who didn't do A level maths really struggled with the maths course in the first year.
The good news is that after the first year you hardly ever see maths again, but if you come across it, it's pretty basic.
He said that in his final exams he only needs calculator in one out of seven exams.
He would recommend that, if at all possible, to find somewhere to learn a bit of basic calculus as a head start to first year. This will also make first year much easier.
Everyone in the first year finds maths hard, but first year of Biochem is very hard in general.
Hope this helps.