I agree with the poster above, there are a lot of legitimate reasons to take time out, but to take there years off to maybe get into a specific course at a specific university it just stupid in my opinion, especially considering how competitive it is. Submit a strong application to make up for other things (ie. good PS, good entry test score, good interview) and if you don't get in move on, I'm sure you'll get offers from other good universities. Oxford is not the be all and end all, so don't make stupid rash decisions just to slightly increase your chance of getting in.