Not a Giffard, suspiciously like a Greener though

[Geezer]

So, now that I have had time to think about this, a Martini action it is. Almost certainly 577/.450 cal as it is unlikely to have been .303. They were Lee Enfields in the main.

Minor point of gunspotter trivia.

There were a lot more Martini-Enfields than most people think. At least a couple of hundred thousand, probably more, mostly converted from M-Hs. They did unglamorous duty in non-infantry roles, reserve units, Cadet forces, etc. Some bits of the Indian armed forces were still issued them in WW2.

The Martini-Enfield (and its rarer first iteration, the Martini-Metford) is Britain's forgotten service rifle.

Of course, everyone wants the M-H, not the Enfield variant. No licence now required, and if you are like me you watched Zulu on TV every Boxing Day growing up. "Front rank, FIRE! ......"