Ooooh
I'd soooo like it to be 6th DG...My grandfather was in from 1896...The early pic (1st one with jam pot cuffs...) might well have had him on it....
I also have a 6th DG riding crop, almost exactly like the one in the last pic....
But.....
As granddad was in South Africa with the Regt, and had QSA and KSA medals I would have expected to see at least some uniforms with them on...especially the RSM!!!
There appear to be no medal ribbons around at all, just the one chap with one medal on the first pic...
Have you found his attestation sheet??