English Bracelet' marks

Hi, please help to find a maker name of a beautiful English bracelet. I think it was made in Birmingham in 1851. Letters JS for a maker. It also has a mark (last one) that I don’t understand. Any help would be great
Thank you,

This is a mark of Joseph Smith & Sons of Birmingham. The date letter C is 1977. Note that the queen’s head mark is not a Victoria duty mark but a special commemorative mark for the Silver Jubilee (25 years as Queen) of Elizabeth II.

I don’t understand the last mark either - it is not an official part of the hallmark.


Thank you so much.