I was actually finished at the dentist (for this round anyway - contrary to my expectation that wasn't the end, I have two more appointments to come, deep joy) about half past twelve and I could have made it, but it was such short notice I had some other things planned, and in any case it was tipping it down and I'd rather go to the Kelpies on a nicer day. Next time.
In fact I ended up taking Hilda to hospital - or rather the bike shop. She fell over while parked on a windy day last week, and I noticed on Sunday afternoon that her derailleur was out of alignment. Attempts to fix it only seemed to make matters worse, I think I'm going to need that spa day tomorrow to get the oil off my hands, and in the end I phoned the bike shop in Peebles. "We've gone out of business, try one of the shops in Innerleithen." (That was a real person, I believe they only went out of business the previous day.)
First shop in Innerleithen said he was on his own, really short handed, couldn't do anything for another four weeks or so. But try one of two others (tacit warning-off as regards the other shops in the town). However, in conversation he was able to identify the problem for me. Apparently there is a sacrificial part in these complicated derailleurs called a "derailleur hanger" which is designed to fail if the mechanism takes a hard knock, to protect the rest of the mechanism. He said it sounded as if that's what had happened, absolutely fitted with the observed symptoms, and as these things are frame-specific they need to be got from the manufacturer. So called Ribble where the assistant pointed me to the right item on the web site, and ordered one. I called the next bike shop on the list who said, sure, just give us a call when you get the part and we'll fix it. When I got home from the dentist the part was there, so I called, and he said, just bring the bike in. So I did.
Despite my having said that I'd never been to the shop before, the guy there took one look at Hilda and said, haven't we had that bike in before, several times? I said no, never. Apparently there's someone else in the neighbourhood who has a Hilda clone. So at least they have some experience on the model. Hope to get her back at the weekend if all goes to plan.