Gap year to apply for engineering at Oxford?

Hi all, I currently have offers for deferred entry to study engineering (mechanical) at Durham, Manchester, and Exeter - I will be firming Durham and insuring Manchester.

Considering how well my mocks went this winter, I expect to be getting the equivalent of A*A*A*/A in my national education system. I was therefore considering reapplying to uni in September to aim for Oxford.
However, I don't really know if it's worth me giving up my offer from Durham to risk getting rejected from Oxford?
Would there be much difference between getting a degree in engineering from Durham and getting one from Oxford?

Thanks for your help!