When Jane and Thomas are discussing the photographic film in Thomas's house, there is a pillow with the number three on it propped up vertically against the back of a couch. A little later, this pillow has moved to the top of the back of the couch at the point where the arm meets it and no one has touched it.
When Jane tries to sneak out of the photographer's home with the camera, her hairstyle radically changes from the way it was upstairs to a different style when he stops her. When they go back upstairs it's suddenly back to the old style.
When the mimes stop Thomas in his car at the beginning of the film, the entire film crew is reflected on the side of it when we are given the shot from behind them. When it returns to the view from the passenger side we see that a single old man is walking by on the other side of the street.
Just before the Telephone box goof, when the photographer gets out of his car and walks towards the phone box, for a split second a crew member's arm is visible behind the wall on the right of the shot.
The hawthorn is in bloom in the park one day and entirely missing the following morning, though still in full leaf. It is clear that the second "day" was filmed in midsummer, some weeks after the first.