The Daemons - S8-E5
Continuity mistake: The hoofmarks seen by both Yeats and Benton from the helicopter appear to be huge when seen from the air. Yet, when the helicopter lands, the hoofmarks are suddenly much, much smaller.
The Daemons - S8-E5
Continuity mistake: After completing the third summoning ritual, the Master turns towards the spot where Azal is about to appear. He has his arms lowered and Jo is stood to his left. In the next shot his arms are up, and Jo has moved to being in front of him.
The Daemons - S8-E5
Revealing mistake: When the Brigadier crosses over to the RAF and the plane, you can see the plane is a model with a stick to control it just under the nose.
The Daemons - S8-E5
Continuity mistake: In part one, watch for the continuity error when Miss Hawthorne turns to face the policeman: her cape appears and disappears from around her shoulders from shot to shot.
The Daemons - S8-E5
Plot hole: It is never explained who - or what - killed the man in the churchyard during the first scene (early in part one). It cannot be Bok (the gargoyle) or Azal (the Daemon) as neither of them have awoken.
The Daemons - S8-E5
Other mistake: When the Master is in the cavern, he lights the candles with a taper, then shakes out the taper which snaps in half.
Answer: TARDISes are generally available for properly authorised use on Gallifrey; they're not usually assigned to a particular Timelord on a long-term basis. The Doctor stole his when he left his homeworld.
Tailkinker ★