^Okay, that would explain it, then. Thanks.
But it's amazing how much of Doctor Who
was shaped by the perennial labor (sorry, labour) disputes at the BBC. Like how the early Tom Baker seasons were shaped by the ongoing dispute over which union was responsible for the TARDIS console -- the set department said it was a special effect, the FX department said it was a set piece. So we never saw the console room in Baker's entire first season, and then a couple of years later we got the retro wood-paneled console room with the simpler, time-rotor-free console.