There are a couple of Lads on here who are pretty good at finding out details of units / regiments etc. But i think they would...
Sorry I'm not one of these lads, Smurfy, but I see that there's only one wearing shoes and a sam browne, so I'm guessing that it's a platoon or troop photo, rather than a squadron or company affair and he would be the troop officer with a WO next to him wearing a sash. Could be a cadre of some sort, but every last one is wearing what looks to be the same medal, so perhaps it's a presentation ceremony/parade and the WO is the RSM. They're all in kd of some sort, so it's most likely overseas, it's not the colour of kd from my time though. All wearing caps and black belts too, so doubt if it's one of the armoured regiments, perhaps foot guards, artillery, or pbi. I counted a few moustaches so reckon it was taken pre-war. And now you're no wiser! Cheers, Syd.
Going by the uniform, the peaked cap, the shape of the badge, the Officer and the Sergeant (with sash) and the fact some are wearing the NI GSM. I would have a guess at this being a platoon from The Royal Green Jackets in Hong Kong in 1978.