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I can find no marks in Grimwade that match this mark for London. However the dating of 1720 —1740 is supported by the owners initials of I E , with a barred I, which on spoons was apparently in common use from at least the late 17th century until the mid 18th and is not found later.
I personally think it is London - the style and execution just feel wrong for provincial, but this is only a gut feel.
The only provincial possibilty seems to be Robert Makepeace although none of his marks in Gill are similar. However the first of his recorded marks is on the Newcastle copperplate in the 1728 to 1730 period and it is known that Makepeace was working earlier than that date.
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