Hi Dudley,
This is absolutely fascinating! Thank you for posting. And there's a story to it...
The clue is in the name of the sender and the abbreviation 'D.C.O. I.Y.'. The latter stands for the Duke of Cambridge's Own, Imperial Yeomanry, which was eventually numbered as the 47th Company. The D.C.O. formed part of Spragge's ill-fated 13th Battalion I.Y. whose survivors surrendered to Piet Cronje at Lindley in May 1900 having been cut off from the remainder of Roberts's force and besieged for three days. More details on this site.
All the Troopers in the D.C.O. were wealthy 'gentleman troopers' (asides the officers' servants). What made them unique is that they volunteered to serve in South Africa without pay and to provide the costs of their own equipment, horses and transport to the war. They donated their Yeomanry pay from the government to the war widows and orphans fund. The D.C.O. were massively oversubscribed and only 110 chosen - one rejected gentleman even asked for a medical certificate so that he could prove his rejection to his wife.
Despite their wealth there was only one thing the Troopers wanted - the Queen's Shilling! As reported in The Times on 25 January 1900:
"The swearing in of recruits took place at Duke Street (St James's, London) yesterday under Major Morland, approving officer, and Lord Arthur Hill, in his capacity as a magistrate. The men exhibited much eagerness to be possessed of 'the Queen's Shilling' as a memento of the occasion and the wish was gratified".
W.S.K. Hole was one of those Troopers (he's recorded on this site)!
I am currently researching the story of the D.C.O. for a book on the 13th Battalion (the other companies were the Irish Hunt and two from Belfast) so I am thrilled that your post confirms The Times account! Please could you send me the jpeg of the coin and envelope for my files - I'll IM you with my email address if you agree.
I have some other mementos of the 13th Battalion that I will post on this site in due course.
Best wishes,
Justin