Vintage sterling silver empty coin mount brooch

Condition: although complete and functional, the clasp hinge doesn't work. 

Hallmark: D&L (maker / sponsor), standing lion passant (sterling silver), letter m (year: 1911), anchor symbol (Birmingham assay)

Suitable for a coin diameter of 28mm

Internal diameter 27mm, external diameter (which includes the edge detail) 32mm

Approx weight 3.9 grams