A hay rake was put next to the rock wall by the killer after dragging the fox in the bag around the hunting area. In a later shot near the end of the fox hunt, the hay rake is pulled away by a tractor for a clearer shot of the field of hunters. After the dog sniffs out the killer, the killer jumps a horse over the wall and gets killed on the hay rake as he falls from the horse.
The closer shots during the fox-hunting scenes were shot in a studio using rear projection. In these shots, wires can be seen holding the actors and allowing them to move up and down as though riding real horses.
Gwendolynne La Doll's address is shown on the manuscript as being on Fulham Road, London S.W.8., and later dialogue describing the location as "the Fulham Road" makes it clear that this means the main street of that name. But this runs from Fulham to Brompton, whereas the SW8 postal district lies across the Thames in districts such as Battersea and Wandsworth.
The goof item below may give away important plot points.
Immediately following the initial explosion of the large, DC-8 sized airliner, a small single engine aircraft is shown, on fire, and starting to spin out of control. The airliner is then seen to be completely intact after crashing in the water. Despite this, survivors and luggage/cargo are strewn about the ocean, and the airliner is shown burning, even though the aircraft behind them is completely intact.