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.
Answer: It was never destroyed on-screen; it was intact at the end of the TV movie, and destroyed by the start of the 2005 series. It was destroyed in the novel "The Ancestor Cell," but in a completely different manner to what happened in the series.
DaveJB