I bought a couple of Paxettes off ebay spares or repair. The first one had had the same trouble as mine, but it was easier to see how the parts go together. The second arrived at the weekend, and I unpacked it last night. The shutter was jammed. Well, they seemed to have switched it to self-timer during an exposure, so a bit of gentle persuasion got things moving again. All shutter times except one second working just fine.
Neither of the Paxettes had the extinction meter, which I'd been interested in playing with as an aside, but both had a fun little uncoupled RF. Not as nice as the coupled RF of my Super, but OK generally (though a quick test shows that it's much easier for the right eyed). And the latest camera has an interchangeable lens - a Pointikar 45/2.8. I'm not sure if that's better or worse than the Staeble Kata.
I'm half tempted to keep the latest one and get a longer lens for it too. But what I really want is to get my Super up and running again. Looks fiddly.