Place of Origin:
Terror of the Autons
Mary Farrel was the wife of John Farrel and the mother of Rex Farrel.
After her husband was killed by a Nestene-controlled plastic troll doll, she was questioned by the Third Doctor and Jo Grant, who both learned that The Master had taken control of Farrel Plastics. (Terror of the Autons)
BEHIND THE SCENES
Mary Farrel’s full name is not mentioned on screen in Terror of the Autons. It is only mentioned in Terrance Dicks’ novelisation, Doctor Who and the Terror of the Autons.