Ipcress et al....thanks for the help. I just wanted to share with you the most recent response from the pewter society....so this thread could have some closure. This is a copy of the e-mail sent to me from Roger Barnes;
Dear Jeremy,
My previous fears have been allayed and the crown and staffs touch mark has now been identified as being that of the pewterers Burgum and Catcott of 2, BristolBridge, Bristol who were active from 1765-1779. The partners were Henry Burgum I and George Syme Catcott . They used a number of different touch marks and labels. They are well known to pewter collectors and were fairly prolific makers of pewter wares and traded to Africa and North America and also producing brass and copper wares. We are most grateful to you for granting your kind permission for the Society to record the marks , particularly the "hallmarks" which we think have not previously been found and for the two touch marks which are much clearer than the single one we currently have recorded. for them. Experts on Bristol pewterers have now been involved in the research and we will advise you if anything further comes to light.
Best wishes - Roger.
Who knows....possibly the engraving and date on the front marked an anniversary or some such. Thank you all again.
Jeremy