Should probably avoid all mathematics-based majors, including CS. Finance will likely be okay, at worst it is number crunching and algebra. Economics is an easier alternative to Finance, a popular choice among stupid normies.
You are unlikely to be accepted to a school that is above your ability, but if you're worried about it, you can test yourself using something like the SAT (
https://satsuite.collegeboard.org/practice/practice-tests) and look at schools where the average SAT score is below your result. Of course, the SAT is an American test and the UK may have a different equivalent.
Success in university is mostly based on being able to consistently do small amounts of work without burning out, getting lazy, or partying too much. In all likelihood you won't find it too demanding.