That is quite bizarre. Those EM bulkheads, even if they have LEDs fitted, still only give out a limited amount of light designed to light up a corridor or the space outside directly around a fire exit - at 6m up in the air their effectiveness will be questionable. They should have fitted IP65 rated twinspots.
It did the last time I tootled past on the Transpennine Express.I too noticed this station lamp in 2008 whilst waiting for the Deltic 55022 "Royal Scots Grey" on RetroRailtours excursion to Edinburgh and back.
Interestingly, these lanterns were quite common on many stations in the Manchester area. They were never used on the platforms themselves, but could be found lurking on pathways within the station environs. There used to be a good selection at Hyde North on the Rosehill-Piccadilly line, the pedestrian walkway to Dinting station on the truncated remains of the Woodhead route and also a few on the Bury route stations. I think the Stalybridge example is probably all that is left hereabouts.
Yeah there aren't many Z8260s left around Manchester nowadays... there was at best 2 on Salford Central a couple of years ago (though these will likely go if the Ordsall Curve gets the go-ahead), and there's a canopy of one on the southern approach into Bolton. On the former Woodhead route, there's at least one at Hadfield where the platform used to continue in the direction towards the tunnel
Trowbridge station has had its car park improved and new LED lighting installed. The lanterns are black and a look like a shorter and bulky version of the Urbis/Schreder Teceo.
They may be the new shape version of the OrangeTek TerraLED, however their website and images online only show the original version of the TerraLED. Mazeteam had some images of the new version fitted to concrete columns, but these are no longer showing on the forum.. I'll dig out the photos. The originals had been on a Facebook page, so it seems odd they're not showing as the page is still running. If I can't find the photos, I do have very easy access to TerraLED lanterns so can take new photos.