Im in same situation. The uni im looking at require grade 6 for maths. I havent got this I only have a 4.
Ive heard a mix of opinions.
Perosnally I think that GCSE are a bit outdated when you go to uni, like its quite irrelevant at that stage, they mostly care about your recent A level grades. Think about it, unis arent really going to care about your SATS grades, are they? SATS,GCSE, A-level qualifications is pretty much just to get you into the next stage eg secondary school, sixthform/college, uni.
My closest friend , goes to Manchester University and has no english or maths GCSE. she's studying law. i obviosuly know you dont really need maths for law, but it just goes to show that they CAN be flexible. My friend got through standard application, but theres always an option to go through clearing.
Im sure if you meet the a-level entry requirments itll be fine.