I want to take 3 A levels while doing a foundation year in accounting and finance

I'm currently studying accounting and finance with foundation year at kingston uni. It really gets into my head knowing that I used to be really good academically and messed up my chances at a russell group uni, but unfortunately I lost my drive during sixth form and came out with horrendous grades. I was studying maths, further maths and physics and I want to retake those three WHILE doing my foundation year course and maybe transfer to UCL, Bristol or Warwick next year. I'm not sure if this would be possible though becuase I think that would be a lot of pressure, but I have heard of private school kids taking 5 a levels. If I want to go into investment banking would it be smarter to continue with this course and ditch my dream of going to a russell group? Just for extra information I did achieve 3 8s (A*s), 4 7s (As), 6,5,4 for my GCSEs.

I'm currently studying accounting and finance with foundation year at kingston uni. It really gets into my head knowing that I used to be really good academically and messed up my chances at a russell group uni, but unfortunately I lost my drive during sixth form and came out with horrendous grades. I was studying maths, further maths and physics and I want to retake those three WHILE doing my foundation year course and maybe transfer to UCL, Bristol or Warwick next year. I'm not sure if this would be possible though becuase I think that would be a lot of pressure, but I have heard of private school kids taking 5 a levels. If I want to go into investment banking would it be smarter to continue with this course and ditch my dream of going to a russell group? Just for extra information I did achieve 3 8s (A*s), 4 7s (As), 6,5,4 for my GCSEs.