Alexander Lethbridge-Stewart

In an alternate universe seen by "James Gore", Alexander Lethbridge-Stewart was a grandson of Gordon Lethbridge-Stewart. (PROSE: The Man from Yesterday)

Alexander was the brother of Alistair Gordon Lethbridge-Stewart. Alexander married Olivia they had a son named Henry Lethbridge-Stewart. Henry went on to marry Olivia and have two children, Julius and a daughter. (PROSE: Faithful Friends: Part 2, The Man from Yesterday)

Behind the scenes
The use of the name Alexander is a potential reference to Alexander Stewart, the Brigadier's son from the unmade film The Dark Dimension.