The Doctor (The Ultimate Adventure)
The Doctor (Face Value), as this was the first valid story in which he appeared
Talk about it here.
In a different continuity in which Crystal had instead travelled with the Sixth Doctor, she saw a version of the Doctor in a dream prompted by her belief that his sixth incarnation had died. She noted him wearing a Greenpeace t-shirt. He later turned into a tall man. (PROSE: Face Value)
Behind the scenes
This incarnation of the Doctor was originally featured in the stage play The Ultimate Adventure, and has been informally dubbed the "Greenpeace Doctor" by fans, after his t-shirt.
In the play, the Doctor met his companion Jason in his native Revolutionary era France, in 1789, having narrowly saved him from the guillotine. Later, they travelled to London in the 1980s where they met Crystal and, later, Zog. Together, they fought the Daleks and the Cybermen. (NOTVALID: The Ultimate Adventure)
This incarnation dressed in contemporary 1980s clothes including a beige coat and trousers, a brown hat, and a Greenpeace t-shirt. (NOTVALID: The Ultimate Adventure)
Casting
This incarnation of the Doctor was created when Jon Pertwee, who reprised his role as the Third Doctor in the stage play, fell ill just before a performance on 29 April 1989. His understudy, David Banks filled in as the Doctor for the remaining two performances. Another actor, Chris Beaumont took over Banks's usual role of Karl.