silver pocket watch markings.

this is some marking on a pocket watch that belonged to my grandad could anyone tell me some more about the marking please

This is a Chester Assay Office mark. I read the date letter as “U”, for 1858. GR is the maker of the watch case. He was George Roberts, a Liverpool watchcase maker, watch maker and watch importer.

Hi thank you very much for your helpful reply .do you know what its value would be the hands are missing the post to wind it has gone and the plate that holds everything in has become un rivoted if you get me.thanks for your time

You are probably just looking at the scrap value of the case.