The first appearance of Richard Johnson as Brigadier General Ffolkes. He would reprise the role in Season 4 "Faith and Beggorah" (1983). Subsequently, both episodes have an underlying storyline involving Ireland.
The first of two appearances by Robin Dearden (Mandy) in the series. She would later appear in Season 2 "The Elmo Ziller Story" (1982).
The rank of Brigadier General was abolished in the UK armed forces in 1921. Poor research.
There is a reference to a "Mountbatten affair". Lord Louis Mountbatter was a highly prominent member of the British royal family and mentor of future king Charles III. He was assassinated on his yacht by the IRA via a radio-controlled bomb on August 27th, 1979. This episode, which aired 13 months afterwards was inspired by that crime.