I came across some different information regarding Bob Monkhouse and the confiscation of his film collection.
https://www.filmstories.co.uk/features/b...ime-squad-case/

Many years ago a friend of mine ran a Film Society and hired 16mm films from various libraries. On one occasion he was going to show one of his own features. This was the time of Bob Monkhouse's troubles. So my friend contacted the library which had the same copy and asked permission to show it. The reply came back and asked for the same fee as if he had hired the film from them.

This is probably where Bob went wrong by loaning out some of his collection.

In those years it was almost impossible to buy 16mm features in this country. But quite OK to import them from the US where TV stations were getting rid of their black & white films in favour of colour films.