Reddit reviews Harry Potter Page to Screen: The Complete Filmmaking Journey

It's also mentioned in this fantastic book. It's really pricey, but so worth it if you want a look into how the films were made but can't afford to go to Leavesden.

I hope you're being accidently ignorant. Have a read of Harry Potter: Page to Screen; the amount of work and artistry that went into those films is unbelievable.

According to this:
http://harrypotter.wikia.com/wiki/Category:Images_from_Harry_Potter_Page_to_Screen

The image is from "HP Page to Screen"

I'm not sure about videos, but Harry Potter Page to Screen: The Complete Filmmaking Journey is the most definitive source for behind-the-scenes information about the making of the series. I'd certainly recommend that book over online clips if you're actually interested in learning more about the filmmaking process.

Unfortunately nothing can be published that doesn't go through JKR. She owns the rights to everything basically. Also I guess the idea is that if you want to know about the sets you have to visit the tour in order to "buy" that knowledge.

Pretty much all of the general info is available by watching the special features on the films, going on Pottermore, and also there are a couple of good books which most Interactors work from, like From Page To Screen.

All the gossip and funny little stories come from original crew members though, by word of mouth, and that's the only stuff that isn't really published, along with the tiny details about props and costumes etc, so for that you'd have to visit the tour.