Why go for N1 over N2? I mean other than the time gap, N2 is very good and you can even state that you speak Japanese fluently on you CV as (at least as far as I am aware in the UK) N2 is considered fluent enough for the workplace. Don’t let the idea of the time gap be the reason you take the N1 over the N2, because from what I gather from other people, N1 is more for showcasing how good you are at Japanese, and not for usefulness (not saying its not useful, it just doesn’t provide much over the N2).
If your taking the N1 for personal satisfaction (i.e. your not taking the N2 because you only want to see if you can pass the hardest test), then why does the time gap matter? I mean taking the N2 and passing would show that you are ready for the N1 (or at least you are at the stage where you can start to prepare without worry of any stuff from previous exams catching you out) and therefore you get the extra year to ace the revision for the N1 test and then the test itself. Don’t rush it, I’m not sure it will help you in the long run.
Anyways, whatever you decide, best of luck with it!