When David Jason was asked to advertise Castella cigars in 1988, it seems that he was very much in character as Del Boy.
Below is a beautiful clip of David Jason unsympathetically visiting a mate in hospital. It is circa 1988, so i would expect it to of been filmed around the time the Christmas special Dates was being filmed.
You can almost imagine the pain felt by the patient as he lays there defensively to Dels care free efforts to cheer him up. You have to wonder whether the Great John Sullivan was also involved in the 30 second sketch.
Let us know if you find any other Sketches or adverts