Can someone help me ID this piece of equipment?

I think this is the Observer's Thermal Imaging System (AKA 'OTIS') but does anyone know an L-series designation for it or an NSN? Supposidly these were used in Northern Ireland & the Falklands, so I'm guessing they'd be obselete by now (almost 30 years later) & my reenacting unit would dearly love to get our mits on one of these...

https://www.milsurps.com/images/impo.../Page_05-1.jpg

Back in 84/85 I was a liaison to the Royal Marines, I was a U.S. Marine Air Naval Gunfire f/o. I believe you have a picture of a squad or platoon level O.T.I.S. (tripod mounted) they were used as a RECON tool and to assist anti tank crews. I'm sure they were used in the Falklands, not sure about Northern Ireland. Not much help to you, but brought back some memories.