7th September 1968: broadcast of episode 5 of The Dominators. The Doctor disposes of the invaders by planting their bomb on their own ship; but the Tardis is engulfed by lava…
7th September 1987: broadcast of first episode of Time and the Rani, starting Season 24. The Doctor unexpectedly falls off his exercise bike and regenerates; the Rani then captures him. Mel attempts to escape the bubble-traps but is caught.
It’s also in a collection of CSL’s shorter works – Christian Reflections, I think it’s called – but I don’t know if it’s still in print – I bought it in the 1960s