Would deffering for a year to resit affect my chances of getting into uni?

So I got my a level exam results today and they were nowhere near as high as expected. I was predicted an ABB and got ADD. I didn’t get into my firm choice but I did get into my insurance for engineering. However I am now getting major cold feet about my insurance choice as it is a very different environment and course to my firm choice. I am considering deferring for a year and entering myself as a private candidate to resit the two subjects I got a D in and try to re-apply to uni next year. I am quite happy with this plan but I am worried that this may affect my chances of getting I. to uni next year, if it doesn’t how would I go about re-applying with ucas?

Edit: I would also like to point out that my insurance choice is in London so there is also a financial element in there. I like the idea of taking a year out to save up some more money for uni since I’ve now got a glimpse of how expensive it actually is.