One of these days, I'm going to post an entry about the SU had got something right and hadn't screwed up. I suspect they might be selling thermal underwear in Hell before that happens though.
All in all, it took about 5 minutes to sort out the insurance problem. I told the (enormous giant of a) guy the situation. He looked in his spreadsheet, found my number and gave me the sticker. It seems the info had just been mislaid during Freshers week and hadn't been totally lost. Shame they didn't think to contact folk when they found it. If the nice guy who sorted it hadn't been new, I might have gotten angry. But it's sorted now and hopefully it means I'll have some societies to enjoy for the forseeable future.