All the scenes with the protesting pickets at Rupert Robinson's factory were shot with a single camera, unlike the multi-camera technique that was normally used for TV cameras at that time. Later scenes when Marker visits the factory were shot with the same camera. This is evident because of a small picture blemish about half-way down the frame, close to the left-hand edge. Other outdoor scenes (eg at Robinson's house) do not have this blemish.
In the flat belonging to the students there is a poster on a wall advertising 'The Heavy Metal Kids'. A founding member of that band was Gary Holton who later found fame as Wayne Norris in Auf Wiedersehen, Pet (1983) and who, near the end of his tenure in that series, died in 1985 after overdosing on drugs and before the filming of the second series finished.