Revealing mistake: The explosion of Irongron's castle is obviously stock footage of a quarry explosion.
Revealing mistake: How did Rubeish's glasses manage to improve his chronic shortsightedness when they are obviously plain lenses?
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.
Invasion of the Dinosaurs - S11-E2
Revealing mistake: When Grover and Whitaker struggle over the time machine at the very end of episode six, the console wobbles and jerks as though it were very lightweight.
Invasion of the Dinosaurs - S11-E2
Revealing mistake: In episode four, when the Doctor is being herded through the complex, the walls wobble very badly whenever the metal shutters slam down.
Invasion of the Dinosaurs - S11-E2
Revealing mistake: When the Brigadier is using a flare to ward off a dinosaur in the tunnel, the smoke instantaneously vanishes as it hits the split screen.
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: During episode three, in the mining area, just before the city's root appears, the tracks on which The Daleks move can be seen.
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.
The Monster of Peladon - S11-E4
Revealing mistake: When the Doctor and Sarah arrives in episode one, they leave the doors of the TARDIS open and the empty inside of the TARDIS can be seen.
The Monster of Peladon - S11-E4
Revealing mistake: At the end of episode 2 / beginning of episode 3, the Doctor and Sarah are thrown into a pit. It is quite obvious that they hit a flexible mat when they land. it is gone when they stand up.
The Monster of Peladon - S11-E4
Revealing mistake: The mines are fairly obvious set constructions. The floor is flat with some sand thrown on. In addition, gaps can occasionally be seen between the floor and the walls or the floor and boulders.
The Monster of Peladon - S11-E4
Revealing mistake: In the climactic fight at the end of episode four, the face of the Doctor's stunt double can be seen.
The Monster of Peladon - S11-E4
Revealing mistake: Near the end of episode six, when Aggedor is falling dead to the ground, the clothes of the man inside the costume can be briefly seen in a gap between Aggedor's leg and foot.
Planet of the Spiders - S11-E5
Revealing mistake: In episode three, when Tommy peers into the room where the Doctor and Sarah are talking to Cho-Je, the camera moves forward - and bumps into a wall with an audible thud and noticeable jerk.
Planet of the Spiders - S11-E5
Revealing mistake: At the very beginning of episode four, the thin pole moving the queen spider can be seen.
Planet of the Spiders - S11-E5
Revealing mistake: In episode one, when a psychic wind is blowing everything all over the Doctor's lab, look for the hatstand standing steady as a rock.
Planet of the Spiders - S11-E5
Revealing mistake: A bad CSO match up occurs in episode one, when Clegg is making the breakfast tray float across the room. The Brigadier is looking at a point some distance from the CSO'd tray.
Planet of the Spiders - S11-E5
Revealing mistake: When Mike and Sarah are in Mike's car going to the monastery, the car swerves off the road and Mike is replaced by a stunt man.
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