Hey man, not sure if this is going to be any help,
Have you looked into foundation years at any universities? I like you have no level 3 qualifications, although I am a little younger at 21, I want to study physics and have also been a little worried about not being fresh enough on my maths and physics. So I looked into the AHE courses, however they're very limited around my area, so contacted many universities that would accept me as a mature student without any level 3 qualifications on a foundation year, to which I got a few positive responses to say they would definitely consider me and encouraged me to apply over the AHE course. So that's what I've done. Maybe take a look at them?
I know Aberystwyth, Bristol, York, and Liverpool definitely take on students without level 3 for the foundation year, but there will be definitely more!