South Croydon was a London suburb. Sarah Jane Smith and her aunt Lavinia lived on Hill View Road there when Sarah Jane travelled with the Doctor in his third and fourth incarnations. Sarah Jane asked the Fourth Doctor to drop her there when he took her home to Earth. (TV: The Hand of Fear) He mistakenly took her instead to Aberdeen. (TV: School Reunion) K9 Mark III was delivered to Lavinia's South Croydon home in a crate for Sarah Jane in 1978. Sarah Jane had already moved out of the house by that time and was travelling extensively. (TV: A Girl's Best Friend)