Kenneth Williams plays W. C. Boggs, the father of Lewis Boggs (Richard O'Callaghan). In real life, Williams was only fourteen years older than O'Callaghan.
On the close up with Sid sitting on the chair, you see two knitting needles, one on either side of his jacket. When Beattie and Sid are in view, the jacket completely covers the knitting needles, next shot, close-up again, needles seen again.
In W.C.Boggs' office, when Charles Coote has just designed a toilet, Sid decides to test it and sits down on it and reads a Racing paper. Charles says, "It was hardly designed as a reading room." In the next shot he can be seen saying the word "room" again but with no sound.