During the wrap up scene, Steed paints a cupids heart on the wall and signs it JS. The camera then cuts to Mrs Peel and back again the heart. It is clear that this is a different painting than the first one.
When Angora has the door of a van slammed into her face near the end, the bloody wound on the left side of her forehead appears before the door has made contact with it.
Mr. Cheshire's keystrokes on the organ did not match the music being played.
When Erskine is fighting off the cat outside, the top of the backdrop is visible for several seconds.
When Mrs. Peel enters the specimen storage room with the researcher, the shadow of a boom mic can be seen in upper right corner.