Carla Langer

Paul Langer is the husband of Carla Langer, and father of Clyde Langer.

Either, her mother or mother-in-law — Clyde's grandmother — lived at Lavender Lawns and tipped off Clyde on strange happenings therein. (SJA: Eye of the Gorgon)

Clyde was explained to have been with her during the events of Earth's transportation to the Medusa Cascade and its subsequent invasion by the Dalek fleet. (DW: The Stolen Earth)