I just finally heard the BBC adaptation of this (finally getting around after many years to the adaptation of the Casebook stories), and I was surprised by a seriously wrongheaded decision made on the part of the producers.
Some picklehead decided that since "The Retired Colourman" was the last episode they would ever produce (as they were going by book publication order of the canon), that it should be treated as if it were the final case Holmes handled before his retirement. This is just wrong, wrong, WRONG. Internal evidence in the text story clearly dates the adventure as taking place in 1898, at which time Holmes still had several years left before his retirement to the downs. "Retired Colourman" wasn't even the last story Doyle wrote, that was "Shoscombe Old Place", "Colourman" just happened to be the story put at the end when they were collected into book form.