First and only appearance of the Radio-controlled (Space) Dumper.
Although the flashbacks are ten years earlier, the aliens' red spacesuits have the silver bands of the later episodes rather than the silver chains of the pilot and earlier episodes.
David Tomblin's original script had a few different plot points than the filmed episode. Originally, in 1970, Straker had arrived at the farm house investigating reports of a UFO in the area and witnessed Catherine running away from there. Following her, he trailed her to London, where he ended saving her from a rape attempt by a lorry driver. In a complete state of panic, she ran off again, taking "the tube" to Edgware Road and threw the cylinder off a bridge over Little Venice. While continuing to flee, she ended up being run down by a bus. Now in the present, after reviving from her coma, Straker must take steps to get her to remember her experiences, as he had by now forgotten the location of the farm house himself. In this version, although Catherine actually survives the aging process, Paul Foster reports to Straker that the drug used on her has killed her. Straker's reaction causes Foster to realize that Straker had fallen in love with her.
This episode takes place in 1980.