If you're predicted AAB, why not apply to another AAB uni, since you already have 3 backup uni's? And if you aren't too confident you'll get an A in maths, still apply to 2 AAB uni's, and change Reading/Keele to a Uni which requires a B in Maths.
But in answer to your original question, I know Salford only asks for BBB, as do most Met's.