The newspaper shown several times mentions a UFO sighting. The character Romany Rose was played by Wanda Ventham, who appeared nine times in UFO (1970) as Colonel Lake. That series dealt with a secret government organization trying to stop UFOs.
Geoffrey Whitehead plays Dr. Gregory Ransom in this episode. He returns in episode 16.4, The Flying Club (2014), in the role of Giles Wilding.