Remembrance of the Daleks - S25-E1
Trivia: This story is set weeks after the time frame in which the very first Doctor Who episode, "An Unearthly Child", took place. There is a scene in a house, with a TV in the corner, where the continuity announcer begins to announce the start of a new Saturday early evening science fiction story - it is the announcement which launched Doctor Who - which cuts out just before the title is mentioned.
Remembrance of the Daleks - S25-E1
Trivia: This episode establishes that I.M. Foreman's scrapyard at 76 Totter's Lane is where the Doctor collects his post.
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