Emma is seen at the beginning of the show watching episode #4.3, "The Cybernauts" on TV.
Christopher Lee and Patrick Macnee acted together previously when they attended the Summer Fields School together. In each of their autobiographies they praised the other as the better actor.
The so-called Ministry of Defence Neoteric Research unit, or at least its main entrance thereof, was actually that of the Haberdashers' Aske's School Elstree....just down the road from the late-lamented Elstree Studios. The gates date from the time that it was the stately home of Aldenham House. The bridge at Tykes Water (a very pretty and totally rural location in the school grounds) was extensively used for incidental shots, and also for the opening sequence in the Tara King series.
Christopher Lee's first major role was as the creature in Hammer's "The Curse of Frankenstein". In this episode, he wears a similar costumes as the creature and plays a character called Frank N. Stone.
Christopher Lee and Patrick Macnee were both pupils at Summer Fields School and were involved with school amateur dramatics.