Hi,
Welcome to the Forum.
The likely candidate is Briddon Brothers of Sheffield. Platers often used a variety of marks, the one we have for Briddon Brothers can be seen at:
http://www.925-1000.com/silverplate_B2.htmlYour pieces would pre-date 1897 when the use of the 'crown' was outlawed on Btitish plated wares in order to avoid confusion with the official mark of the Sheffield Assay Office that was used on silver.
Trev.