Hammer: The Studio That Dripped Blood (1987)
https://www.youtube.com/watch?v=R4k6mRMw9fk - from the Cinema Garmonbozia YouTube channel (48 mins long).

The blurb:
“A retrospective of the films of Britain’s Hammer Studios, renowned for making stylish horror films in the 1950s, '60s and '70s, featuring interviews with Peter Cushing, Christopher Lee & Martin Scorsese among others.”

The House of Horror - Memories of Bray (2013)
https://www.youtube.com/playlist?list=PLCqISFK17hERfshH-ZWlVnmCTnm1n6Jd4 - playlist from the official Hammer YouTube channel (5 videos, ca. 10 mins each).

The blurb:
“Discover how a manor house in suburban England became known as ‘The House of Horror’ in this 5 part series charting the growth of Hammer Studios.”