Many Thanks dog nose. I have searched endlessly for any examples of this now that I know what I am looking at I can see, well a very worn example of one.
http://s1307.photobucket.com/user/clarisping/library/ I was given a rectangular locket and was interested in the silver marks on it but when I looked into them I became unstuck at the city mark, the only thing I could find that was similar was a dutch marking. It looks like an arrow head on it's sid...