I have the two metal dogs, which I assume are early Buchanan adverts for Black and White. If it is any help at all, I bought them about 15 years ago in a junk shop in Norfolk for about 50 english pounds. The shop owner didn't know what they were though, and thought they were just ornaments.
I am trying to find a history of the black and white dog figures, with no success at all - anybody know of one? I have a gradually increasing collection of this ephemera and would like to know more about it.