Thanks for the response, @Always"watching". I ended up buying a 'stopped' from ebay (turns out the screw on the crown wheel was loose, and thus could not wind). I replaced the pallet fork with the one form the donor, and all is well again. It's a reasonable practice movement to get to grips with, possessing only a center seconds complication and, being considerably larger than a wristwatch movement.
I expect I'll be here far more frequently now I have found this forum, and its wonderfully warm natives.