Assistance with Maker's Mark

[Argentum2]

I recently came across this mark for a Sheffield maker CB&S but I have had difficulty in identifying it and the period in which it was used. Any assistance would be much appreciated:

[dognose]

Hi,

Cooper Bros. & Sons Ltd., Don Plate Works, assayed at Sheffield in 1967. The firm were acquired by Frank Cobb & Co. Ltd. in 1983.


Cooper Bros. & Sons Ltd. - Sheffield - 1966

Trev.

[Argentum2]

Many thanks for that, Trevor.