Changing course at Warwick (From MPhys to MMathPhys

So I just got my offer from Warwick for MPhys Physics (A*AA) which I'm pleased with of course. However, I recently decided that I would really like to do the 4 year Maths + Physics course (MMathPhys) at Warwick instead of just straight 4 year Physics (MPhys). Do you think I can contact them now and request for that to be organised, if so, how should I go about doing it?

Thanks!

Predicted A*A*A*A* in Maths, Further Maths, Physics and French (dropped Chemistry in which I got an A at AS last year).

Just to let you know: I emailed them and they got back to me within 24 hrs saying it's fine; I've received a formal offer now (acknowledged by UCAS Track) for the FG31 Course (Maths + Physics), which is cool! Thanks guys..