The set-up was as follows. There were two identical bluescreen rooms, each with three walls and no ceiling. They were built adjacent to each other in the center of Angila TV's large Studio E on Magdalen Street in Norwich. The area for the helpers was set up in the corner of the same studio.
Mostly, the right-hand blue room was used for superimposing the dungeoneer onto the background, while the left-hand room was used for live close-ups of hand-operated puppets such as the dragon's head, and the flying dragon.
The right-hand room used a luminescence-sensitive chromakey system, so live shadows which were cast affected the brightness of the superimposed dungeon graphics. The room was reasonably consistently lit; any variations in brightness of the walls was transferred to the graphics, but this didn't usually matter as it was quite subtle and the shape of the real/virtual rooms typically matched up anyway.