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Possibly R Carr is the silver Smith but not sure but it is defiantly from Shelffield and 1976, I have had a few of these ingot but marked up with RC in a hexagon

Yeah, all the ones I found only had the RC hallmark. Not sure what the JS is all about.

JS may be Jock Stokey, he included that himself.

Thank You @vgholdingsllc Great Info and all I had to do was ask for Help, that's what I love about STEEMIT !

Happy to help. If you get a sec go check out my stackitis post from earlier, good for a laugh.