A level French with no prior experience?

Almost all schools will teach it from GCSE with the GCSE as assumed knowledge. Unless your school is telling you otherwise, you'd need to learn a lot very quickly

I'm an international student coming to England for sixth form, and I somewhat stupidly chose to do A level french when I have no prior experience in French. I start in Spetember. Should I attempt to learn the GCSE course in the next 5 months and get fully up to speed? Or just learn at my own pace and catch up once I start school

Yes the requirement for entry was a 7 at GCSE but I'm not doing any GCSEs and joining at sixth form so I could just choose whichever A levels I wanted and for some reason chose French. I can still change but I want to give it a go, if I just do a lot of duolingo between now and September will I be able to catch up once I'm there?

I'm an international student coming to England for sixth form, and I somewhat stupidly chose to do A level french when I have no prior experience in French. I start in Spetember. Should I attempt to learn the GCSE course in the next 5 months and get fully up to speed? Or just learn at my own pace and catch up once I start school

Final year French degree student here. I'd say your plans to do A-Level French and the replies to this thread are a bit optimistic. A-Levels are in part meant to prepare you for university study, and if by 'no prior experience' you mean that you're going to try to teach yourself the French language from scratch to pre-degree level in a few months, you are going to need more than Duolingo. It depends on the school, but my lessons were mostly taught in French and, as you may know if you've looked at the curriculum, you will be expected to write essays based on analysis of books and films, not just study grammar and vocab. Not to mention you will be doing oral exams too.
It's up to you, but if you don't have access to tuition and you don't think you will be able to maintain the motivation to study for several hours per day until September, I would strongly recommend switching to something else. Ultimately, you need to give yourself the best chance of getting a good set of grades if you want to go to university. When doing an A-Level language, you are likely to be up against native speakers and people who have been studying the language since childhood. So you'll be at a major disadvantage there.
If you feel confident enough by September and your school allows you to switch A-Levels during term time, maybe you could attend lessons for the first couple of weeks and then make a decision. But if that's not the case, maybe you should reconsider and look into opportunities to learn French outside of school in your spare time.

My school gives me the option to drop a subject at February half term, up until that point I will be doing 5 subjects (maths, fm, history, theology and philosophy, french) if I do french up until then, and then drop it, but do badly, will that affect my university applications at all?

There's no point in doing 5, especially if you're planning to drop one. I would suggest not taking one of your subjects at all and consider dropping one of the other 4 at a later point.

For some reason my school requires anyone who wants to take further maths to take 5 until at least the febuary half term, I wouldn't if I didn't have to

My school gives me the option to drop a subject at February half term, up until that point I will be doing 5 subjects (maths, fm, history, theology and philosophy, french) if I do french up until then, and then drop it, but do badly, will that affect my university applications at all?