This is probably a long shot - but take a look at the lower left of the diagram "Makers’ Marks- Bow Porcelain" at https://bowporcelain.wordpress.com/2013/05/06/bow-porcelain-school-project/
Thomas Frye is described on Wikipedia at https://en.wikipedia.org/wiki/Thomas_Frye
Well done, I searched hard but not hard enough I reckon, great info and much thankful. You all are a great bunch!This is probably a long shot - but take a look at the lower left of the diagram "Makers’ Marks- Bow Porcelain" at https://bowporcelain.wordpress.com/2013/05/06/bow-porcelain-school-project/
Thomas Frye is described on Wikipedia at https://en.wikipedia.org/wiki/Thomas_Frye
I would agree that it's a Bow China Works, London mark for which the period would be c1747 – 1776.
The bothersome thing is that this particular mark is generally assigned as from the early part of that period (c1750), but as an inscribed mark not a painted one. I guess there are always exceptions for every 'rule', so I would be inclined to give invent4hir a hefty pat on the back and say he's probably correct that it's early Bow.