The Celts and Britons have long talked about the Sidhe, the True Folk , that took people and returned them years later, unaged, with stories to tell. Bill called the Doctor on this...albeit briefly. Is the Madman in a box aware he is mucking about?,,,YES It would explain a lot.... I love the stained -class representation of the TARDIS , and Wilford's reaction... I think the 9th Doctor was responsible for that, when we (and Rose) first met the Doctor (again). And 12 knew the deal.... EDIT: A question...Accent : When the Doctor speaks, the accent is of Ynys Prydein. Consider which dialect the TARDIS determines to be correct...
The Seventh Doctor era, particularly the books, took him straight into a kind of Celtic new age mysticism...which is a logical standpoint going back to the Third Doctor and the Buddhism there. It sort of continues well into the Eighth Doctor...but never really fully resurfaces. The apocryphal Death Comes to Time really plays with the epic myth stuff too, and leans heavy into the Merlin iconography and symbolism. Doctor Who was really at its best before it came back in some ways, and it’s a shame Big Finish only pays lip service to that era, when it basically owes its existence to it via Bernice.