The Talons of Weng-Chiang - S14-E6
Continuity mistake: Magnus Greel puts Leela in the distillation chamber and switches it on. Cue red lights, special effects, and Leela writhing about. Then the Doctor arrives and throws a battle-axe into the works. Sparks fly, and the machine stops, presumably broken. Later, however, when Greel is pushed into the chamber, it turns on and does its thing just as if nothing had happened to it. Oh, and the axe thrown earlier disappears too.
The Talons of Weng-Chiang - S14-E6
Continuity mistake: In episode 1, when the Doctor and Leela leave the TARDIS, the door is open and is not moving. They then walk away from the TARDIS for a few seconds. When they hear the attack on Bullard (the Cab Driver) and run past the TARDIS again, the door is magically closed.
The Talons of Weng-Chiang - S14-E6
Continuity mistake: When the Doctor smashes the crystal lattice on the floor, the deactivated Mr. Sin flinches.
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