Visible crew/equipment: (Ep. 2) When The Doctor, Jo, and Dr. Tyler are taken into Omega's palace, in the first shot of the multiple passageways (right before Jo says that it looks like Aladdin's cave) the curved chalk actor's mark is visible on the floor, then we see it again in three following shots. Note that when they're all escorted further inside, just as Dr. Tyler comments about the matter/anti-matter not making sense, Jon Pertwee looks down, presumably to make sure he hits his mark.
The Cousins - S1-E37
Visible crew/equipment: At his office, Mr. Castle looks at the newspaper and shouts, "Flat, flat, flat, it has no flavor, there's something missing," and just as the secretary snaps back, "Martin Lane," we can see a crew member's hand reach up to help shut the door at the bottom left side of the screen.
Visible crew/equipment: When Uncle Joe shows up at the delivery entrance to the Pixley Hotel, the shadow of the boom mic swings into view at the left side of the screen.
Continuity mistake: In part 1 and part 2, the character that Donald Harron portrays is noted as "Art Harris" in the opening credits of both episodes. The problem occurs during part 2, where the character is repeatedly referred to as "Ray" Harris, the FBS Deputy Director. (00:05:15 - 00:05:50)