Visible crew/equipment: During the final chase, Jaclyn Smith's double stuntwoman is extremely evident. (00:43:45)
The Bermuda Triangle Crisis - S2-E4
Revealing mistake: When Wonder Woman drops a mine into the water, she's supposed to be dropping it into the ocean. However, you can see a drain plug of some sort in the background and the "ocean" is obviously a pool, or similar.
Continuity mistake: Near the end of the show, the squadron has to land on a carrier deck. The shots from the sky go back and forth between a straight deck carrier and an angled carrier deck. Also, an angled carrier wasn't put into use until the early 50's by the British, Black Sheep takes place in WWII.
K is for Kill: The Tiger Awakes (1) - S2-E8
Visible crew/equipment: Steed is seen driving along with Purdey and Gambit in rural France. The camera was probably mounted on the front passenger side door, pointing in. As they near their destination, the camera pans to reveal a farm house, and as it pans, a professional-looking microphone can be seen sitting on the dashboard.
Revealing mistake: Jamie prepares to split a giant heavy log in two, with her bionic arm, so that it will fit into her fireplace. Just as her arm comes down, you can see the middle seam where the log was pre-cut for the shot, so that it easily breaks in two. (00:00:30)