GCSE options don’t really matter as long as you pass English and maths. For a level I think you need chemistry and one other science. I’d say you need a level bio and chem. then just pick something else, it helps if it’s science or maths based but if you hate math’s obviously don’t do maths. I did them two and psychology, it’s got really basic maths like averages and it’s quite interesting. Be prepared to do a decent amount of maths tho, nothing too complicated since you get equations- chemistry has loads of maths but you’ll need to do it.
I think you need grades AAB- ABB but it depends on the uni some want higher and others don’t really mind. Check on the uni websites for the specific requirements because they will be different. You get to apply to 5 unis so have a good look at them all.