I felt this episode was... OK. Not good, not bad, just... There. The villains felt a bit tacked on. Like we couldn't just have an episode about the witch hunts, we had to have a monster of the week with a generic conquer the world plot.
This was a very weak episode. Throwing king James into it was a particularly odd decision, as well as the attempt to make him out as a more or less well meaning buffoon.
The actual Witchfinder General Matthew Hopkins as a straight up, non-sci-fi historical villain would have been far more interesting.
Thought this episode was probably the best of the season so far - going back to the good old "turn up somewhere in British history, find some weird stuff going on, get rid of the aliens who are inevitably causing the problem" Who. Glad it wasn't in Cardiff or London this time.
i like Alan Cummings' King James - overacted, but, well, it's Dr Who isn't it.