Thanks trev for your reply.
Indeed, the sponsor's mark is on all three trims of the baton, H dot W in a lozenge. I hadn't noticed them. I don't know if they could be referring to
Henry Williamson.

However, I didn't quite understand the sentence
It was likely un-necessary for the plaque to be hallmarked due to the weight being less than required.
It seems to me that the plate is heavier than the individual pieces on the stick, which are instead hallmarked correctly.
Do you think the plaque is also 9 karat gold?
I see that there is a very noticeable color difference between the plate and the baton trims, which tend to be copper in color.

I have several photos and objects that were presented to Signor Grossi, since one of his daughters lived near Bologna.
Best regards
Amena