inschool - thanks. I figured it was something to do with that, but at least I know what it's called now.
I can't think why it would be operational after I've locked up, but then I remembered that the odometer light stays on for something like half an hour after turning the ignition off. I wonder if it's the event of shutting that off that's causing a short and it having a quick spasm?
The windscreen wipers had moved in the hour or so it took me to put my shopping away last night, so it must be something in the first hour or so of the ignition going off or locking the car. Once it's done it, it doesn't seem to happen again.
Anyone any idea what the exact delay on the odometer light is, so that I can watch it?
Trouble is, unless I can make it do it I'm a bit stuck for getting the dealer to look at it, or know when it's fixed.