Nobody can make that decision for you, obviously. However, there's also a halfway step of Computing & IT and a Second Subject, with the second subject being Maths.
Just ask yourself this: Do you want to be the type of person who studied Maths and Physics, or you do you want to be the type of person who studied Computing and IT? You have a powerful opportunity to define a part of yourself by this choice, so take the best advantage of it.