Season 7 finishes on the 20th of June 1970, and Season 8 debuts with "Terror of the Autons" on the 2nd January 1971.
Another gap of 27 weeks, meaning that Doctor Who is now absent from TV screens throughout the whole of the summer and the autumn, and is only on TV a couple of weeks shy of half the year. This will be the norm from now on, and it is tempting to see this "less is more" approach directly paying back in increased viewing figures.
Indeed, Season 8's debut story (introducing two popular recurring characters and a popular returning monster), starts relatively strongly at 7 million, climbing to just over 8 million 4 weeks later before inexplicably dropping to 6 million at the start of the second story "The Mind of Evil".
However, although the series now completely consists of discrete episodic stories with little or no continuity between them, by the end of the season it's difficult to see this reflected in the viewing figures. There is no real pattern to the peaks and troughs, at least nothing arising from the series itself. Viewers don't disappear at the start of a story and slowly increase towards the end, only to drop off again the week later. On viewing figures alone, the show is certainly more popular than it was during Seasons 6 and 5, and about as popular as the Troughton stories of Season 4. But it still isn't approaching the dizzy heights of Season 2.
Perhaps this is a continuing symptom of Doctor Who no longer being a special or unusual product. Certainly the early '70s were awash with similar (some almost identical), shows featuring the same glam Sci-Fi aesthetic - "The Tomorrow People", "Ace of Wands", "Jason King", "Doomwatch" - although if it hadn't spent the last 4 years shamelessly reinventing itself, Doctor Who might have been doing far worse in the ratings war...if it even still existed.