so i did some research, sent a few emails and this is what i have to feedback-
Keele: only accept resits of A Levels once they have obtained the grades. So if you're sitting your A2 exams in 2018, you'll have to apply for 2019 entry. They require the B in GCSE maths, but may waiver based on the admissions officers discretion if your application is stellar.
Bristol: doesnt provide much information, but GCSE maths is required at an A. You can only resit any subject once.
BSMS: Doesnt mind if you retake the GCSE during your gap year or alongside your A Levels.
Exeter: accepts resits without discrimination.
these are the four uni's im looking to apply to for 2019 entry after my gap year. I'm going to resit GCSE maths this year, as its free in my college.