As noted, page 246 is in the TR4-6 section; but there is a description of an optional factory "grille guard" starting on page 245 and extending onto 246. No photo, but the text notes that it "attaches to the bumper inboard of the overriders, and doubles as a badge bar." I am guessing that it refers to the item shown below (taken from a scan of a TR4A factory accessory brochure supplied by Darrell Walker).
I doubt that the item shown on eBay is factory; most likely it is one of the huge array of aftermarket parts that used to be available for these cars. (Or it could be that the "elderly lady" was mistaken, and it's actually for a Land Rover LR3 :laugh: ) As long as I'm peering into my crystal ball, I'll also guess that it was intended to replace the original bumpers rather than supplement them.