Duncan Urquhart and Naphtali Hart entered several marks together, the first being on 18^th October 1791 and the latest on 22^nd August 1805.  They were registered as buckle-makers and as plate-workers.  Naphtali Hart entered a mark on his own on 10^th April 1812, so it would be reasonable to assume that they were working together up until this time.

Grimwade only pictures one maker’s mark for Urquhart and Hart, simply referring to the fact that there were several.