Hi Rob You dont need any qualifications in maths beyond a C grade or equiv for QTS the last time I checked. What you do need though is multi layered. You need to have an ITT provider who can see beyond a very basic qualification you have in a specialist subject. You need to be confident at delivering the curriculum which doesnt require a piece of paper but the more you know the better. Can you explain things to the weakest GCSE pupils? can you motivate? control behaviour and inspire kids. If so then the level of maths knowledge will levelled from there. You will hit many a brick wall though if you state you want to teach maths with such a basic qualification despite what you may know.