I hadn't studied maths at school and I'm now on track to graduate in accounting & finance with a first. You don't need it. Obviously having an understanding of advanced maths is beneficial, but is A level maths crucial? No. The maths associated with accounting is basic. Financial maths is slightly more complex, but still relatively easy. Most, if not all, unis will also make accounting & finance students take statistics which again, is complex but not overly so.