Your current grades won't really suffice for the top chemical engineering universities like Manchester, Imperial. This is because they require you have at least an A in Maths. Universities such as Cambridge would demand you have an A-level in Physics (if you're taking the engineering route).
But all in all, I would urge you to get an A-level in Physics and bring your Maths grade up to an A/A*. While you're at it, if you can, get an AS in Further Maths as this will also strengthen your application.
Happy days!