I don't know how many people visit that part of the site, does anyone know anything about a watchmaker called J.B. Courty? It is (or was) a French firm.
that looks a fairly comprehensive list, but i also found a horrogical forum (they seemed liek a nice lot of fanatics) it looked quite intense, I'll try to find it again
You could try sending a letter to this firm, which is a watchmaker in the Gironde. If anyone knows about watches with the name 'J B Courty', I'd expect this guy would. (It might even be the same family):
Horlogerie Courty
23 bis route de la Mole
33770 Salles - France
Thanks, I've just put this watch in for repair and the mender knows nothing about it, he said it's quite old, not very quality (1 jewel) brass case byut it's got a stopper (it stops the watch) on it which he said he'd never seen before.