I was wondering if anyone knows what a rare Guinness Advertising Bulldog made by Robert Porter for Royal Doulton would sell for, or knows of another existing anywhere. I think it was made around 1920's and has black writing on the coat saying, 'Guinness Light Ale' Robert Porter & Co. Liverpool England. There is also a matching plate. I have a few with the blue print on the coat, which were made later. Please anyone who knows anything please respond.