Hi,
Unfortunately, I can't direct you to a source that is likely to satisfy you. To find a mark that looks exactly like yours is akin to finding a needle in a haystack. Of the fifteen or so images I have of Hester Bateman's mark, the two clearest are at
http://www.925-1000.com/dlLondon2.html#MThere are some underlying factors in the British marking system and the life of a piece of silver that have to be taken into consideration when evaluating a maker's mark.
Firstly, the marks are hand stamped, when the die is struck with the hammer the pressure is rarely, if ever, perfectly dead center, so the mark is usually more well defined more towards one edge, or corner, than another.
Secondly, the pieces were marked in an unfinished state before being sent to the assay office for hallmarking, on their return they were then given their final polishing, an abrasive process that often has negative effect on the clarity of the mark impressions.
Thirdly, over the lifespan of a maker's mark diestamp, it
evolves. Each instance of use wears it down, so an impression from a stamp used in 1780 will be markedly different from the impression the same diestamp leaves in 1788, how different depends on the use it has had and the care taken of it.
Finally, in the 220 odd years since the creation of your piece, it has been polished 50, 100, 200 or more times. Each time the further abrasion of polishing has had a deleterious effect on the maker's mark, changing it even more.
What this all boils down to is that even though the same maker's diestamp may have been used over its lifespan to mark 1000 or 5000 pieces, every one of the impressions it made is truly unique and unlike any other. This is one of the things that make researching silver marks far more interesting then the pastime may seem at face value.
Hope this helps and BTW, I'll eat my hat (an acquired taste, but I'm beginning to get used to it) if that is not a Hester Bateman mark.
Regards, Tom

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