Visible crew/equipment: In episode 2, as K-9 seals the wall panel, watch out for the hand which emerges to hold it in place.
Visible crew/equipment: After Chris exits the TARDIS with the medical kit, Romana places the collar around the Professor's neck. When Romana tells Chris that Chronotis, "Should be able to think with it," in the next closeup of Chris the moving boom mic is visible at the top of the screen, before he kneels down.
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