Hi adeline.g
I've just graduated from Lancaster with an MEng Chemical Engineering. I would advise you to check admissions policies for the Chem Eng courses at various universities, most specify that you need to do math and one or two physical sciences. Physics is not an essential, it can normally be any two physical sciences for example my A-levels are in Chemistry, Computer Science and Math. For Lancaster, the current entry requirements for Chem Eng say an A-level and math and A-level in a physical science either physics, chemistry or biology so you would be eligible for Lancaster course with your current A-level choices.
Most universities will have open days where you can ask this to an admissions representative for the Engineering or Chemical Engineering department so try attend some of these as well. The representatives might be able to provide more information or offer avenues in which you can still apply with your current A-level choices.
I hope this helps and if you have any other questions feel free to get in touch.
Paddy - Lancaster Engineering Student Ambassador