Woodbridge Antiques has dated this piece to the 1920s.
The maker's marks are also very clear for D.N.H & S.

Each is a good heavy gauge silver and feel nice to hold in the hand, a very fine pair indeed, in antique collector's condition.
Hallmarks and maker's marks: Sheffield 1920 by D.N.H & S
:
Condition: The napkin / serviette rings are in great collector's condition. The circular presentation is also in great condition for age and use.
Measurements:
Each napkin: 3.2 cm width and 4.4 cm diameter width approx.
Combined weight of both napkin rings: 64.3 grams approx.
Weight inclusive of box: 113 grams approx
Woodbridge Antiques has dated this piece to the 1920s.
Specialists in quality antique silver, fine jewellery & accessories
You can view the stock and full dealer information on the Woodbridge Antiques Profile Page