It is not my specialty, but they look Malay, or Indonesian...and the fact they've got British gear and what seems to be a non-Malay officer riding in front suggests the Malaysian Emergency. There's also something about it that suggests a counterinsurgency, no? Not mass troop movements. Just doing a quick Google search turns up some photos of Malayan Police and Special Constables that are inconclusive- or send you down the rabbit hole of Pinterest.

Then there's that SMLE, which by the time of the Emergency would have been mostly replaced by the No.4 Mk1, or the Jungle Carbine, the No.5 Mk1. But maybe not replaced everywhere? It's really hard to tell from the photo which model SMLE it is- the distinguishing details are pretty small, like whether the cocking piece is flat with notches or a knob, whether there's a magazine cutoff.