Five Clues to Fortune (1957)

I recently found this clip from Five Clues to Fortune, a 1957 film produced by the Children's Film Foundation. It features three very Fifties children, one of whom is played by the young David Hemmings.

In his memoirs Blow-Up and Other Exaggerations, Hemmings remembers making it:

This gave me the opportunity to get to know the technicians behind the making of films and I soon established a strong rapport with them. It seemed to me that they went out of their way to be kind to me, letting me sit in the pub in Woburn village with them at lunchtime, learning three-card brag and the mechanics of film-making. 

Ever since then I have always had an affinity with the technicians behind the scenes in movies. This experience undoubtedly sowed the seeds of my subsequent move from the front to the back of the camera.

The experience did help his acting though:

I learned a great deal from it, among other things how to ride a horse (which came in very useful fourteen years later, when I played Captain Nolan in The Charge of the Light Brigade).

The sources agree that the safari park at Woburn did not open until 1970, but there was clearly already a collection of animals there when this film was made.