Christine Bush's father

Christine Bush's mother and father were very rich. (PROSE: Spiral Scratch)

When Melanie Bush's grandfather inherited Hallam Hall, he decided against moving his family there on account of its size and instead leased it to the National Foundation for Scientific Research. John Hallam moved into the top floor upon joining the Foundation. (AUDIO: Catch-1782)

Mel told the Seventh Doctor that one of her grandfathers died in World War II, although she did not specify whether it was Christine's father or Alan's father. (PROSE: Just War) Her only memories of her other grandfather was of him making her laugh. (PROSE: The Best Joke I Ever Told)