The uni I applied to said that you could contact them to make sure the access course you pick was one they approved, and so I sent them the details before starting my access course. I've just applied so can't tell you if I'll be successful, but it won't be because of my access course because I know thats accepted. The uni I applied for specified how many grades you needed in biology, so there was a set number in biology that needed to be distinction and then the rest could be merits. If you contact the admissions team for the uni you're wanting to go too they should be able to give you direction. You could also get help from mature student support from the unis as you're over 21.