they do sometimes but it will have to do with your interview as you got a good IB score
either way in UK you can find a part time job the minute you will land or you may even ask in the Student Union for financial aid ( if the Oxford Union offers any ). They can also find you a job in the Union or even better in the Uni! or at worse case scenario you can even get a student loan.
get in touch with your tutors to help you out! they will give you all the options you may have in Oxford
Good Luck
