Oh b*llocks.
I've lost my blog template.
It happened like this: Blogger have changed the way that their blog templates work, and added a load of new features that you can only use if you "upgrade" to one of their ready-made templates, like this one, which I'll be modifying presently.
You can, experimentally, "upgrade" your template, which is okay, because they save a copy of your old code and you can switch back. This I know because I did it several times during the day trying to work out if I could cheat somehow and use the new features without rewriting the entire blog.
Apparently I pushed the wrong button this time, because now I'm stuck. Oh dear. I quickly got the cached version of the dob-log from Google, and e-mailed it to myself so that I can rewrite it more easily.
So there you are.