The photo of Tegan's Aunt Vanessa, one of the items created by Marriner from the contents of her mind, was shot specifically for the filming, requiring Delore Whiteman (who had played the character in Logopolis: Part One (1981)) to be contracted for a one-day photoshoot
The ball gown worn by Lynda Baron was made especially for the serial and was the most expensive costume on display.
The Doctor replaces his stalk of celery with one from Captain Wrack's ship. Rather curiously, both stalks come from buffets which are essentially figments of other people's imagination (Castrovalva and the Buccaneer both being "unreal").
This episode was watched by 6.2 million viewers on its original transmission.