The dog got left in the car without taking her lead off a while ago, and she showed what she thought by biting the end off (one of the retracting type). I've just got round to taking it apart and fixing it. I noticed that the mechanism works off a spring -just like a quill return spring from a mill or drill. So if you need a quill return spring for some machine that you can't buy them for, this could be a cheap source for a spring to make fit. I saw aldi or lidl or someone had these leads for a few pounds recently (in the same flyer as the cheap digital calipers).
Regards
Kevin