Margaret Waterfield was the sister of Edward Waterfield and the aunt of the Second Doctor's companion Victoria Waterfield. (PROSE: Birthright)
In her diary aboard the TARDIS, Victoria described the walls of Sir Charles Westbrooke's house having the "sort of design Aunt Margaret always accuses of causing her a headache." (PROSE: The Age of Ambition)
She was murdered by thugs who served Jared Khan in London in 1909. (PROSE: Birthright)