Laura June Hudson plays the ill-fated Elderly Woman. She had been a BBC Costume Designer on the original show, working on eight stories between 1978-81. Tom Baker declared her his favourite, loving her operatic style.
Playing Timothy Drake, discoverer of The Devil's Chord, is Jeremy Limb. He's the son of 1980's Doctor Who (1963) composer and BBC Radiophonic Workshopper Roger Limb.
The TARDIS elects to materialise in a spot recreating the cover of The Beatles' 1969 album "Abbey Road"; even the white VW Beetle on the left (reg. LMW 281F) is present. This is all clever camerawork, as the scene wasn't shot at Abbey Road at all.
In the manner of earlier Doctor's shouts of "Allons-y!" or "Geronimo!", the Fifteenth cries "Hadi ama!" - Turkish for "come on!"
In Radio Times magazine (issue: 16-22nd December 2023), showrunner Russell T Davies teased this episode as being "wildly fantasy", saying: "Episode two next year is wildly fantasy. Completely making up scenarios on-screen that we've never been able to show before."