The hallmarks show a Birmingham assay around 1911. The year hallmark is difficult to make out. It looks like a lower case "L."
The maker's mark appears to be WHH in a rectangular shield with cut corners. A gold presentation plate is soldered to the medal's front. The suspension ring has a lion mark on it, also, out of sight.
I have scrutinized the Online Encyclopedia of Silver Marks, Hallmarks, and Maker's Marks, but have yet to find a section in it on British makers' marks.
Pictures of this medal are attached.


I will be gratefully indebted to anyone who helps.
ps. I noticed the design is engraved by hand. The design is not uniform, and the cuts that make the filigree have traces of saw marks.
Also, the year letter is for 1910, not 1911 as I originally posted.