I can't suggest a candidate, but I don't think Robert Williams is likely. He was working in the 1830s and 1840s, whereas these tongs look late 18th century.
If pushed I would guess, because of the engraving, that they weren't made in Britain.
I first took these tongs to possibly be American because of the decoration, but that is unconfirmed. So because of their style, I thought I would try the old UK on an off chance. Thank you both for your inputs.
I love tongs with hallmarks inside the bowl. I don't have much else to add but it seems like an American homage to English Georgian style tongs. The corn motif is in place of the traditional English bright-cut design. I once found a pair of French tongs from the first empire circa 1800 that was an amazing copy of an English Georgian style tongs. I hope the maker is found.