Where & When
Although no specific date is given in the story, it’s stated to be set approximately five hundred years after the events of The Moonbase. Depending on whether Parry is rounding up or down, and how far we want to adjust for the known dates of future Cyberman stories, this places the story somewhere between the late 25th and mid-26th centuries, with most fan theories leaning towards the later date. This is probably shortly before the founding of the original Earth Empire.
It takes place on the planet Telos, a few weeks' travel from Earth. Given the date, this most likely places it in our own galaxy (although one of the audios will later contradict this), but in the relatively unexplored fringes beyond the edge of human colonisation, perhaps even on the opposite side of the galactic nucleus from Earth.
