I would also note neither Oxford nor Cambridge are in London, greater or metropolitan
They both assess applications somewhat differently, and also it will vary a lot between subjects, so your first step should be identifying which subject you want to study, and then you can figure out which might be best suited to you!
Bear in mind each has a number of subjects unique to that university (e.g. ASNAC/HSPS/Natural Sciences/Land Economy at Cambridge and PPE/CAAH/several languages offered in Oriental Studies at Oxford), and that Oxford has a large number of joint schools, but only single honours sciences, while Cambridge has Natural Sciences and mostly single honours courses otherwise (including, notably, philosophy, which is only available as a joint subject at Oxford).
Hi thanks. I want to study English literature and if possible along side creative writing.
Oxford's English literature course requires you study Old and Middle English in first year; you can study either or both at Cambridge, although I don't think they're required. Oxford has a number of joint schools with English, namely with modern languages, history or classics (the latter having a number of link papers in classical genres of literature through the ages, such as epic, tragedy, and comedy). The History & English course requires an interdisciplinary dissertation combining both subjects, and has an extended essay combining both subjects in second year as well.
On the creative writing front, I think Cambridge might offer some creative writing courses separate to it's degree programmes through the Institute for Continuing Education (ICE), which is sort of a separate department of the uni offering lifelong learning and continuing professional development opportunities. No idea if there's any special dispensation for students to take courses there (they're normally paid courses otherwise, undertaken on e.g. weekends part time through the year, mainly aimed at working professionals). Oxford has a similar department (not sure what it's called) but I don't know if they have any creative writing offerings (and again, no idea how much these are open or relevant to students on the main degree programmes there).