Revealing mistake: The Filer vs. Filer fight in the lab is very amusing, not only because of the several glimpses of the stuntman doubling for Filer, but also because of the way the "metal" railings around the set wobble as they slam into them.
Revealing mistake: The "crystal" tube holding Sarah wobbles whenever it is touched.
Revealing mistake: In episode one, as the Doctor is repairing the buggy, one of the patrol runs on too soon, realises that he's come in ahead of his 'cue', and runs back.
Revealing mistake: Watch really closely when Leela throws the knife at one of the robots. You can see the knife fall to the floor about a second after she throws it. Then, of course, the next shot shows the knife sticking out of the robot's chest. Guess Leela isn't quite as good a shot as we thought.
Revealing mistake: When a Cyberman's arm is sliced off by the Robot's shuriken, you can see his real arm bulging out at the right side of his body. (01:00:25)
Destiny of the Daleks - S17-E1
Revealing mistake: Right after Davros yells "The Daleks will rule the universe," in Episode 3, one of the Dalek operators accidentally starts to lift the top off his Dalek before the scene ends. (00:17:35)
The Tomb of the Cybermen - S5-E1
Revealing mistake: The Cybermen retreat into their tombs backwards; this was achieved by simply having the film of them coming out of their tombs run in reverse.
Destiny of the Daleks - S17-E1
Revealing mistake: When the Doctor and his companion are running past explosions in the sand, you can see the scrape marks from where the effects team covered up the holes containing the charges. (00:13:00)
Invasion of the Dinosaurs - S11-E2
Revealing mistake: At the beginning of episode two, the soldiers firing at the dinosaur are aiming up and well to the left of the creature.
The Talons of Weng-Chiang - S14-E6
Revealing mistake: A 1970s newspaper - the headline concerns Denis Healey, Chancellor of the Exchequer in the 1974-79 Labour Government - can be seen in Litefoot's laundry basket in episode three.
The Dalek Invasion of Earth - S2-E2
Revealing mistake: When Barbara is throwing her bombs, she grabs the window frame in front of her, which wobbles alarmingly.
Revealing mistake: When the Doctor and Jo see Bessie in the middle of the rocky area, there is the white chalky substance from the ground on her wheels, indicating she was driven to the spot rather than being "transported" to the black-hole.
Revealing mistake: In episode 6, during the generally poor fight sequence between the Brigade Leader and Greg Sutton, Greg's first punch to the face misses the Brigade Leader by miles. (00:19:10)
The Monster of Peladon - S11-E4
Revealing mistake: Eckersley - who supposedly knows the mines better than even the natives of Peladon - drags the queen through the same set twice, once each way.
Attack of the Cybermen - S22-E1
Revealing mistake: When Lytton stabs the Cybercontroller, some of the Cybercontroller's 'blood' gets splashed on the camera. (The 'blood' is green-dyed water spraying from the Cybercontroller's arm.).
Revealing mistake: In episode one, a wall wobbles as Benton hammers a nail into it.
Revealing mistake: In episode three, when the root attacks The Daleks in the mining area, the string holding the root up can be seen.
Revealing mistake: When Ace is being attacked by the Haemovores, she strikes one of them on the head, causing its mask to go up and revealing part of the actor's neck.
Revealing mistake: In episode 3, when the second Doctor, the Brigadier and Benton emerge from the TARDIS, the doors are left completely open with the camera looking straight into them for a long time, revealing not only the emptiness of the police box shell, but also that there's a pair of secret doors on the opposite side to the entrance doors. These 'secret doors' come in handy during episode 4, allowing seven people to come out of the police box in the final confrontation with Omega. (Well, it is stated time and again that the TARDIS is "bigger on the inside than the outside". Now we know how that happens...).
Revealing mistake: In the UNIT tracking room, there is a flimsy railing behind the radar operators that Chinn knocks as Yates leads him off to the "direct" phone line, causing it to wobble badly. The Doctor then deals the railing another blow as he comes up to look at the console.
Answer: In 'The Five Doctors', three separate Cyberleaders are definitely used. So it's likely that Cyberleaders are like unit commanders, of which a fair-sized army might have several.
Daria Sigma