Guy Oliver

 was a friend of Edward Grainger.

When Linda Grainger was eleven, her grandfather took her to visit Commander Oliver's submarine. While they were visiting, Oliver had to answer a call to investigate a crashed ship in the sea. Oliver asked for Edward's help during the mission, in which they ended up defeating an alien invasion by the Slarvians. (PROSE: Childhood Living)

Guy later met the Sixth Doctor and Mel when they were trying to defeat the Rainbow. (PROSE: Old Boys)