Castrovalva - S19-E1
Continuity mistake: The Doctor's shoes are different at the beginning of this story compared to the ones at the end of the last story.
Castrovalva - S19-E1
Deliberate mistake: The newly regenerated Fifth Doctor is wearing completely different shoes than the Fourth Doctor did in the previous story. This is deliberate. The boots worn by the Fourth Doctor were actually privately owned by actor Tom Baker. Still, a mistake but this is why.
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 ★