UCL deferred entry

hi all, I am applying to UCL MEng Mechanical Engineering with an A*AA in maths, physics and comp sci with a relatively strong personal statement, however I read online that UCL may not accept deferred entries, or will be unfavourable toward you.

I would really like to defer my entry, however I would like an offer from UCL slightly more, and even though I have already submitted my UCAS i think i may be able to make a substitution, and substitute my UCL application for one without a deferred entry if necessary.

i know i am riding on the boundary for UCL grade requirements, and am not likely to get an offer as a result (non international student also), so any help increasing my chances so slightly would be warmly recieved, thanks