The Vintage Wrist Watch Company has dated this piece to the 1920s.
The watch has a Swiss hand-winding movement, probably by Fontainemelon, which is working nicely.
The watch measures 32mm diameter excluding the winding crown nd the fixed wire lugs.

From 1 June 1907, Stockwells acted as assay agents, facilitating the import into Britain of foreign gold and silver items, which had to be assayed and hallmarked in a UK assay office before being released for retail.

The case is in good condition for such an early piece, just minor surface marking.
The acrylic lens is in good condition.
The dial is in good condition and has Breguet style hands, a subsidiary seconds dial and an outer minute track.
A later leather strap has been fitted.
The watch comes in a new presentation box.
The Vintage Wrist Watch Company has dated this piece to the 1920s.
Specialists in antique and vintage wrist watches and pocket watches
You can view the stock and full dealer information on the The Vintage Wrist Watch Company Profile Page