A* for science?

Could you provide more information please?
Since you did coursework specifically for physics, I'm guessing you're doing all three sciences separately?

We really need to know what course you are doing and what board and whether it is an iGCSE or just a standard GCSE to be able to help you.

Exactly, more background information needs to be given.

my exam board is OCR GATEWAY B and I'm doing further additional science so I get 3 separate GCSEs for each of the sciences

I do it too, but you don't get it for each sub-genre of science(chem,bio & phys)
You get it as:
core
additional
further additional

each one gets averaged out on 3 tests and 1 controlled assessment/coursework

e.g.
C1 % + B1 % + P1% + coursework %
core grade % = -----------------------------------------------
4