Resit A level while in uni, what should I put in my UCAS Application

I already decided to resit my A-level exam next year while I am in uni (my previous college accepted me as an external candidate), as this year I didn't get the result I needed and lost both of my offers (get into my current uni through clearing), so I am going to reapply for uni through UCAS again. Does anyone know if I need to put my current uni in my application? Or can I just leave it out? ( I am planning to send in my UCAS application in late September, so it feels like it is meaningless to put it in my application as 1st year of uni doesn't give me a certificate and it is not a qualification)

Yes, you must.
If you're planning on reapplying anyway, why are you going to uni this year? You will use up a year of student loan funding meaning that if you have to repeat a year, you will be out of luck.

1st year of university does give you a qualification.

If you look at the top of the applications, clearing and ucas forum there’s a stickied thread called University Transfer FAQ. There’s a link in there explaining how to list your university study on UCAS. Universities will always eventually find out about previous university studies although it can take as long as the start of yr 2 for any lies to be uncovered. It’s not a good idea to lie. I know of at least one student who was withdrawn from year 2 of their degree when previous study was revealed that hadn’t been declared on UCAS.

Applying in September before you have properly started your current degree to start elsewhere isn’t particularly appealing to the universities you’re applying to. Why are you applying so early? And why start a degree that you don’t intend to stay on beyond a year?

My clearing choice is not the university I want to go to, but I still believe I can learn something new from it. Reson why I applied early, I got an offer from UCL, but I didn't get the grade I needed, and for this year, I still want to apply to those top universities, so I think it better to send in my application early, which is what I did last year

See the University Transfer FAQ. There’s a link to Oxford’s policy on applying while studying at another university.

Oxford doesn’t accept applications from students at other universities without a reference from the current university and excellent year 1 results. If you want to reapply to Oxford then you mustn’t start a degree elsewhere (or you need to plan to take a gap year after completing year 1 at your current university in order to reapply during that year).

I already decided to resit my A-level exam next year while I am in uni (my previous college accepted me as an external candidate), as this year I didn't get the result I needed and lost both of my offers (get into my current uni through clearing), so I am going to reapply for uni through UCAS again. Does anyone know if I need to put my current uni in my application? Or can I just leave it out? ( I am planning to send in my UCAS application in late September, so it feels like it is meaningless to put it in my application as 1st year of uni doesn't give me a certificate and it is not a qualification)