The Vintage Wrist Watch Company has dated this piece to the 1910s.
Each of the links has the lion silver mark, and one has the Herbert Bushell & Son mark.

Also included is a silver locket, also hallmarked for 1911 and this time with a maker’s mark for another Birmingham silversmith, Albert Ernest Jenkins. The front of the locket has a vacant cartouche. The back of the locket has some unevenness.
It is nice to see a piece where all the components are original to each other.
Total weight 50g.
The Vintage Wrist Watch Company has dated this piece to the 1910s.
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