(1974, Oliver Reed, Fiona Lewis, Derek Jacobi, Anna Gaël)

Obscure and very odd sort-of horror movie co-written by the Marquess of Bath and filmed at his home, Longleat House and Safari Park. Features Reed as a very unpleasant butler, and Jacobi as his master, likely modelled on the Marquess himself. For added curiosity value, the Nanny is played by Anna Gaël aka the Marchioness of Bath, and the Marquess himself also appears as a party guest. Some of this explains the appearance of a safari bus, which I believe to be 932AXL, a Ford 570E/Duple Yeoman new in 1960:

It would have been good to see more of the tourist coaches arriving:

This Bedford VAM/Duple looks smart, but who was the operator celebrating 50 years?: