this is a nifty little doc about the two movies that Peter Cushing made in the 60s. it doesn't really talk about actual "Dalekmania"- like how it got started and that. in fact, the television series is barely mentioned, though one of the writers or producers does talk a bit about the differences between Hartnell's Doctor and Cushing's Dr. Who (which is his surname in the movie).
the doc talks to Roberta Tovey who played Susan in the movies and then to a couple of the other players. they are all very fun to watch and listen to.
Dalek creator Terry Nation shows up as well, in archival form, and talks about the differences as well. this used to be available on some VHS set, but appears to be OOP at the moment. I saw it on Netflix.