The Brigadier (Death Comes to Time)

The Brigadier worked for UNIT and aided the Seventh Doctor.

He managed to stop Tannis' invasion with the help of the Doctor. Ace later informed him of the Doctor's death.

The Kingmaker suggested that the Doctor's death and defeat may have only happened in that universe. (NOTVALID: Death Comes to Time)

Behind the scenes
The Big Finish audio story Zagreus made it even clearer that it was set in a different universe.