@Always Cross I have you listed in the results as a finisher - official check-in time on my records was 20.18, cutoff was 20.21. IIRC we logged the time you rolled over the finish line rather than the time your card was stamped, which was indeed a few minutes later and perhaps strictly outside the cutoff time. Either way, it was close enough that it would have been only the most churlish organiser who filed you as
hors délai. (And since it's a non-BRM event, and therefore not a qualifier for any other event, the rules are more relaxed anyway.)
As far as I know, there are no time/speed stipulations on claiming medals - if you're a finisher, you qualify.
Of course, if you want to attempt to register a faster time for your own satisfaction, to make it more definitive, I quite understand - I think I would feel the same in your position (closest I've ever finished to the cutoff on an event is around 10 minutes, so I've never cut it quite so fine). I see you've already entered this year's event - look forward to seeing you in September!
For this year's event, I'm planning on getting in a stock of medals in advance, so you'll be able to claim one at the finish. Since you already qualify, you could order one direct from AUK right now, but if you don't mind waiting until September, I'll keep one aside with your name on it (although not literally with your name on it, I'm afraid).