Here are a couple of Rolls Royce wrenches. The double leaf-spring-powered spanner is 5 1/8" long and has E46634 stamped on its backside. The front-side boss is "Rolls Royce". This one could have been made in Rolls Royce's Nottingham factory.
The second doe wrench, also 5 1/8" long, has a front-side boss "Rolls Royce Ltd." The backside is embossed, F61016. The opening sizes stamped on the jaw bases, 3/8 and 5/16, have nothing to do with the actual sizes which, respectively, are 5/8" and 1/2" as we measure things in the U.S.A.
A comment on Rolls Royce (RR) wrench prices. It's been my experience that some sellers will sell RR wrenches for up to low 3 figure amounts (and they get it at large auto and steam tractor shows in PA). Other sellers, in more modest settings, will move RR wrenches for a dollar or two. Also, it's important to realize that Rolls Royce in modern times has been, and continues to be, one of the world's major jet engine manufacturers. Are most RR wrenches found today associated with this company's jet engine business?
Auctioneers who publish glossy clay-coated paper catalogs, or the internet equivalent of such catalogs, have tended to overestimate what the real market value of the wrenches they are selling. My lasting impression, as a wrench collector, has been it's always a matter of willing buyer-willing seller. I have yet to buy a wrench from a catalog, or to realize a catalog's price in selling one of my wrenches.