Running away to university

So im writing to ask for help and advice on my situation, i have been living with my family but in the past 2 years things have gotten really bad since they discovered i was queer and that went against their traditional religious views, so im not allowed to do anything they dont physically see, i cant have friends or go out with them, i cant go out on my own even, and theres arguments every other week, for the past 2 years, right now im pretending im straight and have been doing so for the past year and a half to get the abuse to stop, but i dont want to do this for the rest of my life, moving out is non negotiable, as in my household moving out will only happen when im married, which obviously wont happen unless im forced into one. My only way of moving out (that i can think of) is to move to university without them knowing, the university i have in mind is UCL, and they have an estranged student fund, however i dont think that applies to me since im still living with my parents, im in the first year of a levels, and i just want advice on how to leave properly without them knowing, any advice is welcome.

I'm so sorry you find yourself in this situation.
You don't need your parents permission to apply to or go to university and they need have no role in your decision if you don't want them to. The main problem will be finance. Unless your parents are willing to submit their financial information, you will only get the minimum maintenance loan which is no where near enough to live on. Estranged students do not have parental income taken into account, but that can be difficult to prove. Manchester Uni has a useful document on this:
https://documents.manchester.ac.uk/display.aspx?DocID=43944
It might be worth making a post on the student finance section of the student room so that SFE can give you advice.
It would be worth considering non-London universities unless UCL is the only place that meets your requirements as money is likely to be very tight without parental support. Living in the big northern cities is a lot cheaper than London - think Manchester, Leeds, Sheffield, Nottingham, Newcastle, Liverpool etc., and all have thriving LGBTQ communities as do the universities.
Finally, do you have a teacher/lecturer that you would be happy to confide in? This is an awful lot for you to go through on your own.
Wishing you the very best