Thanks Petalpop! 3-in-1 it is then. I’ve been toying with the idea of selling refurbished ones online, but that was the area I really wasn’t sure about.
Martin, thanks for your description of how they work! I don’t have a repairs background, so I just pick things up as I go along.
Incidentally, if anyone has a 3224/6 Keymatic door gasket knocking around, it would probably make a bomb on Ebay! It looks like a fascinating old machine, although I’ve seen what they look like on the inside, and they look like an absolute nightmare to fix! I’m sticking with my Hoovermatic 3314L…
Simon