Since no-one else has dived in yet (c'mon, where are you?), I can rectify one omission in my last post: of course many traditional singers, like Walter Pardon and Cyril Poacher, had a repertoire of music hall and other popular songs, which were the kind of things Edwardian collectors preferred not to bother themselves with. Oh, and I know about Walter P's union songs as well. Doesn't alter the argument, though.