Grimwade #3688, IS&AN, on 1767 ladle

[Sebastian]

Can someone please tell me more about the maker's mark Grimwade #3688: IS & AN (or, IA & NS?).
He says it has been seen on sauceboats with year letters for 1760 and 1761. The mark I show is on a silver ladle with year letter for 1767.
Unfortunately someone in the 19th century decided to emboss it, and the London town mark has been almost obliterated.
Is there a possibilty that NS could be Nathaniel Smith of Sheffield, in partnership with a London agent IA? A bit of a wild guess perhaps.


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[salmoned]

Grimwade's #3688 has a cruciform frame and the center pip has 5 lobes. Your mark more nearly matches #3689, noted as 'unidentified, cream-jugs, 1768 and 1771'.
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