choosing a-levels for medicine

i really want to do medicine at a london russel group uni like ucl, kcl, or imperial. rn i'm aiming for hopefully all 8s and 9s in sha Allah
i am definitely picking biology and chemistry for a levels, and im thinking abt psychology for the 3rd cuz it seems interesting, and i feel like i would enjoy it more than maths. on average i achieve a low 8 in maths, sometimes a high 7, i dont think i'm naturally good at maths and to get a decent grade i have to put it a LOT of effort and time, so if i take it for a level, will i be jeopardising bio and chem? i dont think i'll do an epq since i saw on kings college website that they dont consder epqs at all. so if i do pick pyschology as my 3rd option, should i choose core maths as well? its a new thing being offered at my school and its seems cool, and the teachers also said that people taking core maths wouldn't be getting any homework or work outside of class as its a fairly straightforward subject. so i wanted to know is it worth doing core maths? like will it benefit me at all? or will it make think i'm a low ability student as i didnt choose a level maths? also on imperial's website they say they want a 3rd science subject or maths, what about psychology does it work or not??
sorry i have a lot of questions

i really want to do medicine at a london russel group uni like ucl, kcl, or imperial. rn i'm aiming for hopefully all 8s and 9s in sha Allah
i am definitely picking biology and chemistry for a levels, and im thinking abt psychology for the 3rd cuz it seems interesting, and i feel like i would enjoy it more than maths. on average i achieve a low 8 in maths, sometimes a high 7, i dont think i'm naturally good at maths and to get a decent grade i have to put it a LOT of effort and time, so if i take it for a level, will i be jeopardising bio and chem? i dont think i'll do an epq since i saw on kings college website that they dont consder epqs at all. so if i do pick pyschology as my 3rd option, should i choose core maths as well? its a new thing being offered at my school and its seems cool, and the teachers also said that people taking core maths wouldn't be getting any homework or work outside of class as its a fairly straightforward subject. so i wanted to know is it worth doing core maths? like will it benefit me at all? or will it make think i'm a low ability student as i didnt choose a level maths? also on imperial's website they say they want a 3rd science subject or maths, what about psychology does it work or not??
sorry i have a lot of questions

1) It doesnt matter where you study Medicine, and RG is meaningless. All Med degrees are accredited as equal by the GMC, all follow the same set syllabus and all lead to exactly the same qualification. The NHS will not care where you trained - and your future patients won't ask.
2) 2026 entry requirements for each UK Med School - UK medical school entry requirements - Medical Schools Council
3) Useful Mooc (free short online course) - start any time - Applying for Medical School - Online Course - FutureLearn

Crazy how identical we are

Psychology is a decent subject and there is no reason not to do it as your 3rd subject. You already have biology and chemistry.
You could start doing core maths and see how you go. You could always drop it after the first few weeks if you arent getting on with it/it becomes too much/whatever.