The location of Dr. Sardon's home and laboratory is actually Margam Castle located at Margam, Neath Port Talbot, Wales. This is a very popular location used for many movies and television shows. It was one of the favorite locations used by Doctor Who, the Sarah Jane Adventures, Randall and Hopkirk, Deceased, among many others.
Some of the sets used for this episode came from the episode "The Convenient Monster."
The familiar theme returned.