Today's watch, fresh from the healing bench is a Citizen 21 Jewel "Parawater" (so most probably from 1971). It arrived looking a little miserable, and struggling to tick.
I took a quick look at it shortly after it arrived, and got it going, but I wasn't 100% happy with it, so it received a little more TLC, and is going considerably better. I might be able to get the beat error down a fraction more, but since I decided to quit while I was ahead.
The date changer is also working correctly now too.
Now that it is running reasonably well, and has survived a day on my wrist without complaining, I'm might see if I can bring back a bit more of the original shine.