Warner Brothers Studio Tour London - The Making of Harry Potter
It is imperative that Potterheads attend!
I purchased my ticket online in advance directly from the Warner Brothers Studios website. I found the price acceptable and I had no issue with my ticket purchase or receipt of my ticket.
If you can get to Watford Junction there is an HP official cash only (I believe round trip cost is 5£) shuttle bus that will get you to WB Studios in 15 minutes. There is a cash machine at the Watford Junction station if needed.
The studio itself is magical. I could have cried at any given second taking in all of the props and set items - just knowing that the cast had touched and used these things and that this is where all of the "magic" happened.. it can get overwhelming when you have such an attachment to the books & movies!
I was a bit late for my scheduled entrance time but it turns out that that's not a big deal. I would recommend you buy your ticket for an earlier start time and that way you can take your time through the tour, there is no time limit for how long you spend in the studios but they do have a closing time. I also recommend the audio guide (which is an additional price). I didn't get one and wish I would have - I think it would have added to the experience.
The place was packed and unfortunately I think that will always be the case which is another reason I suggest you go early so that you can take your time and not feel rushed because of the crowd. If you wait your turn and be mildly assertive you will be able to get the photo you want or read the placard at the center of the set you're trying to get to.
The lighting, the crowds, and the sheer number of props do make it difficult to get excellent photos in certain areas so don't expect to get amazing shots. You don't want to see the whole placed through your camera anyway. There are specific sections that are set up for interactive photos and videos. Some have staff members there to assist and some do not so if you're going alone be prepared to ask a stranger for a photo.
Prior to the entrance in the great hall there is a Starbucks and a place to eat as well as a merchandise store and a free coat check. They do offer free WiFi which worked well for me throughout the studios. Halfway through there is another place to eat, there is BUTTERBEER!, and there is an outside area where you can take a break before visiting No. 4 Privet Drive, the Knight Bus, and more.
I spent about three and a half hours walking around staring, touching, and marveling at all the things. It is absolutely worth the visit and I would probably go back again.