Whilst sitting in his office surrounded by paper birds Mr Cromwell says "a very clever chap Mr Harbin". This is in reference to Robert Harbin who had a TV show called Origami (1968) in which he would show various types of paper folding.
In the staff room while Mr Price and David are playing with the gas masks, Doris proclaims that they sound like Bill and Ben. These were characters from a British children's TV program called the Flower Pot Men (1952) who were little men made of flower pots who spoke their own version of English called Oddle Poddle.
While trying to get the TV aerial in the correct position, Mr Cromwell asks Potter to hurry as he may miss Mary Mungo & Midge (1969). This was an animated children's TV program depicting the adventures of a little girl, Mary, her dog Mungo and a mouse called Midge.