When I was about 13-14 years old ('70s), my parents had friends who rented and lived in this mansion. I actually got to play the pipe organ. One thing she didn't mention was the secret passages, disseminated in the wood panelling, between the walls, that allowed you to get from one room to another. I know there is one in the library. There were tennis courts down below the house around the back. I recognise every room that was shown in the video. A lot of fun for a young kid.
"...because of course nobody trusted their servants." As a former servant to millionaires and billionaires, I'd rather take my chances on the honesty of the servants than the honesty of the wealthy. I had to let them know I wouldn't lie for them.