Mary McGinty
From Tardis Wiki, the free Doctor Who reference
Mary McGinty was, according to Sylvia Noble, a little woman with black hair who "worked in the newsagent on Sunday." Donna Noble never really spoke to her.
In a parallel world, Sylvia theorised that Mary had died from the Titanic crash on Christmas 2008, although Donna stated that she might have gone away during the incident. (TV: Turn Left)