Continuity mistake: Right at the end, the insurance man gives Charlotte Jewel Mayhew's letter and in the next shot of him, his hands are empty. But in the following shot he's holding the letter again.
Continuity mistake: During the interview with Maria, her headscarf disappears from Inspector Clouseau's desk. (00:34:28)
Continuity mistake: Marnie's sweater changes after she gets on her horse.