Slightly later than hoped, here are a couple of additional pics which show the reverse and give an idea of size (apologies for poor image quality).
Thanks for the help to date; any further thoughts appreciated.
FECB3039-9DD4-4A1C-920A-D019E2040C00.jpeg 3A214AC4-BE85-48B7-92F6-39C925986F7E.jpg