Revealing mistake: In the end part of this story, in the large spider's den, the string supporting it is visible.
The Dalek Invasion of Earth - S2-E2
Revealing mistake: When Barbara is throwing her bombs, she grabs the window frame in front of her, which wobbles alarmingly.
The Dalek Invasion of Earth - S2-E2
Revealing mistake: In episode 1, one of the windows on the TARDIS is leaning in, but by the time we get to episode 6 it has managed to fix itself. Also when the bridge falls down you can see the poster through the gap, showing that there is no back to the TARDIS.
The Dalek Invasion of Earth - S2-E2
Revealing mistake: When Barbara, Jenny and Dortman are running through the deserted streets of London, in the very last shot, if you look to the left of the screen, you can see some people walking down the street.
Revealing mistake: When the robotic Doctor first appears - and in many of the later scenes involving the jungle on Mechanus - it is very obviously not William Hartnell playing him, but a vaguely similar double. In addition, his lines have been dubbed by Hartnell and do not always match the movements of his mouth.
The Dalek Invasion of Earth - S2-E2
Revealing mistake: When a rebel throws a bomb from the second floor of the Dalek saucer, notice it explodes too early and in the wrong place.
The Rescue - S2-E3
Revealing mistake: At the beginning, as the Doctor is standing in the TARDIS door, the cave wall can be seen through the TARDIS.
Revealing mistake: In episode 1 when the Doctor, Ian, Barbara, and Vicky leave the TARDIS, wheels are visible which move the prop around. There is also no back to the prop.
The Rescue - S2-E3
Revealing mistake: When Barbara fires at Vicki's pet, a firework falls off the gun.
Revealing mistake: In episode 1 when the Doctor is checking the controls you can see the studio lights to the top left corner where the set doesn't completely connect.
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 ★