1N is forcing 2/1 style so could have some stuff.
So slam has a shot here - we don't play any advanced key card ask below 4N or detailed cue bidding agreements, so it's basically 5D or 6D. In an analogous major suit auction I might leave it in 4 or 5 but for a minor suit auction at pairs I think I'd always go 6 here.
Unfortunately, previous board we were treated to a loud conversation from a guy at the next table (where our boards were coming from) on 'LET ME TELL YOU WHY I BID AND MADE SIX DIAMONDS HERE.' (The guy in question is not a complete tit AFAIK, I think he might have been playing with a pupil and wanted to explain things to her, but it was easily audible and he was shushed).
So, can I bid 6D here? The argument 'I always choose 6m over 5m at pairs if it is reasonable' seems a bit different to a situation where you unequivocally have the cards for the bid (does not seem to be the case here). Plus I didn't know the rules for UI from another table so I just bid 5 making 12 for an avg minus.