Thanks for your assistance, Waylander. It doesn't look like anyone wants to disagree with your suggestion of Francis Howden. I only had access to Jackson's Pocket Edition, and he wasn't listed there.
I have a pair of Scottish silver wine coasters that I believe have 1791 Edinburgh hallmarks of Castle, Thistle, L, King's head (identified using the Online Encyclopedia of Silver Marks, Hallmarks & Maker's Marks, which is great). However, I am having difficulty with the maker's mark. This is 2 l...