(at around 21 mins) When Bob Lawrence and his daughter exit the chalet porch to watch the trap shoot, Bob pushes the left door outwards. When the camera cuts to an outside view of their leaving the building, it's the other door that is swinging shut, and it is closing from the inside.
During the shoot-out when Abbott goes over and stands by the window, the pane closest to his right shoulder is broken; only half of it remains. The shot cuts away and then back, and now the pane is intact.
The first time Mr. Lawrence smokes in the Tabernacle church, he is not seen to light his cigarette, yet it starts smoking.
Bob Lawrence picks up a candle stick to use as a weapon when he's hit on the back with a chair; he puts the candle stick down instead of dropping it. He then clutches his face with his left hand and the back of his neck with his right, neither of which were hit.
In the fight in the church, Bob Lawrence struggles with the assassin, rips his top pocket revealing part of an Albert Hall ticket, but in a closeup, the stub is also seen.
When the man is shot through the window, near the beginning, just before he is shot, he turns to face another man. At that time, the beginnings of a blood stain can be seen on his shirt next to his lapel...*before* he's shot.
When the man is shot through the window, near the beginning, he pulls aside his jacket and waistcoat to see the blood, but there is no bullet hole in either of these garments, which there should be as the wound is behind them.