russell group univeristies and gcse results - medicine

So my end goal is to study medicine at a university such as UCL or KCL or oxbridge but my GCSE results were a 99998777776 (6 being art) - i got an 8 in biology and 7 in chemistry as i never really bothered with revision. I'm considering resitting my biology and chemistry gcse's as im confident with ample work i could easily bunk those grades up to a 9, but is it worth it? does anyone know if universities look at GCSE results alongside predicted alevels / supercurriculars?

I'm not going into medicine myself but have a lot of friends who are, and who are applying to the unis you've mentioned.
Those are really strong GCSEs and could absolutely get you into medicine. I'd advise not resitting GCSE chem and bio; the most important thing now is your A levels. The year 12 workload might not seem like a lot now but it gets pretty intense pretty quickly, and revising to resit those would most likely interfere with your new A level content sinking in.
GCSE results, especially for medicine, are taken into consideration, and the more competitive unis would certainly be looking for a high proportion for 7s, 8s and 9s. However, if you're at a state school with generally average/lower grades, I wouldn't worry so much about your 7 and 8 - although, ideally for Oxbridge, 8s and 9s in the subjects you've chosen.
The main thing to focus on now is recapping A level content consistently (don't become complacent!), be proactive - get work experience at an old people's home or ideally a hospital, do a MOOC course the summer before y13 and perform well in your UCAT. I know someone who is incredibly smart and puts in so much effort, got straight 8s and 9s, and is looking at lower ranking med schools because they didn't do as excepted on their UCAT, even though they have all of the qualities needed to be an excellent medic and is so passionate about it. So, apparently, the UCAT counts for a lot.
Speak to your subject teachers sooner rather than later for advice on this stuff; the early entry deadline is Oct in y13.
Medicine is very competitive and a tough application process. Make sure you don't burn yourself out early on, and don't lose belief in yourself. If this is something you really want to do, don't let anyone stop you, you've got this!
Hope this helps, and best of luck!!

DO NOT resit your GCSEs, it would be a waste of a year. Your grades are good, focus on acing your A levels and getting high predictions.