As near as I can tell the hallmarks on the case date it to 1922
There are no other marks except Swiss Made Safety Barrel
Sorry I can't do pics of the movement behind the dial, my hands & watch hands do not get along!

PIC 2

If it is a 9 3/4 lignes movement Roddy it probably is a Felsa Calibre 91. a look under the dial would confirm

It does seem to be about that size as near as I can measure the movement while in the case but I can't find any images of a Felsa Calibre 91 movement on line?

I could not either Roddy, but I have a Master ID book which I got that info from

It also looks close to a Felsa 107

Has the wrong shape Escape Wheel Bridge and the position of the winding bridge plate retaining screw that is right beside the case screw is in the wrong position to be a Felsa 107.

Thanks Bila,
I'm going to have to remove the hands & dial I guess.