https://www.ebay.co.uk/itm/Live-steam-part-built-locomotive-stuff-2-1-2-inch-scale-More-Listed/114576966493?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649
Thanks Ash. They look to be very heavily built, and the flanges are definitely not to the G3S standards.
For somebody speculating on whether or not they are 2 1/2" gauge, and so we cannot trust his estimate, he has placed his measuring stick in totally inept places that do not help us to make up our own minds at all.
At best they might be for a N2.5"G loco, or at worst in some larger gauge.