Nick Hughes:
Thanks for the link – it looks as though one of the relevant illustrations is from a 1935 catalogue, some considerable time after the vice's introduction. My 1933 Brown Brothers' catalogue lists only parallel bench vices but I suspect that the earlier types continued to be popular with the more agricultural trades; BB were, of course, suppliers to the motor trade.
Michael Gilligan:
I take your point about "Photoshopped" artwork and the manufacturer might have left his brand off so as to allow for others to market the item under their own brand – badge engineering.