Retake a level after a biomedicine degree or during?

hi, I have accepted an offer for biomedicine this year but I want to improve my maths a-level grade for the future. Would universities for postgraduate degrees consider me if I did an A level after completing biomedicine or should I do my maths a-level again whilst at university during first year?

Why do you need to improve your maths a-level grade for the future?

My current plan is to do medicine after biomedicine, but just in case my plans change and I want to go into the corporate world I do not know if universities/employers will look at my A-levels and not accept my because my grades are not extremely competitive

Unless you are going into Investment Banking or Law, that should not be a concern if you have great uni grades and relevant experience.