73.75%
An enjoyable story, The Visitation is light fare which adds an interesting race to the series' list of aliens. The Terileptils were an interesting species and I would love to see the Doctor run in with them again. Although the story makes it clear that the Terileptils the Doctor encounters in 17th century England are escaped prisoners, it also made clear that the species are warlike anyway. The same argument could be applied to humanity - how can a love of beauty be reconciled to their love of war? There is a rich tapestry to be explored from all the little hints that Eric Saward has given about the Terileptils.
At the time of broadcast, The Visitation marked the first story since the 1977 story The Horror of Fang Rock to be set in Earth's past. Its almost a traditional story in that it can pique the viewer's interest in learning more about English history. Prior to seeing this I was not aware that there had been a plague in the 17th century. How accurate it is, I leave to proper historians, but I doubt that there is any significant inaccuracy to detract from watching and enjoying this story.
It is interesting to watch it again and spot little continuity touches such as the reference to the previous story (Kinda) even though, at the time, the story had yet to be recorded. Even more interesting is the apparent continuity reference to Pyramids of Mars - well thought out or pure serendipity? On the other hand there are missing continuity references: Tegan is preparing to leave the TARDIS crew, the Doctor has promised to return her to Heathrow airport the moment she would originally have arrived if she had not boarded the TARDIS. It would be "as if nothing had happened" - hmm, what about Tegan's Aunt Vanessa? Has Tegan already forgotten her terrible death at the hands of the Master?
Minor niggles aside, this is a simple but enjoyable story - what more could anyone ask for?