The Silver Cabinet has dated this piece to the 1930s.
The napkin ring is very much in the Arts & Crafts style. It is clearly hallmarked for London 1930 with the maker's mark for Sybil Dunlop.
Lovely!

Dimensions:
Height: 2.5cm
Width: 4.5cm
Silver Weight: 30g.
Complimentary gift wrapping is available on request.
Post and packaging are free within the UK. Overseas buyers please e-mail for postage costs and please note: Import duties, taxes, and charges are not included in the item price or shipping cost. These charges are the buyer's responsibility. Please check with your country's customs office to determine what these additional costs will be prior to buying.
The Silver Cabinet has dated this piece to the 1930s.
You can view the stock and full dealer information on the The Silver Cabinet Profile Page