Jemma is Dan's wife who often appears in his videos. She also has her own channel although it isn't as famous as Dan's. A friend of their's, Leah, is also a YouTuber. Link below. She appeared in the video HAMSTERS! as a person to race Dan in The Great Hamster Race.
In The Sorcerer's Stone, Harry walks with his white owl, Hedwig, through a snowy cloister courtyard located in Durham Cathedral. Harry first learns to fly a broomstick on the green grass of Hogwarts' school grounds, filmed inside the walls of Alnwick Castle, located 30 miles from Newcastle.
Later in The Sorcerer's Stone, Harry sneaks into the restricted book section of Hogwarts Library under a cloak of invisibility. This scene was filmed inside Oxford's Duke Humfrey's Library. Hermione reads about the Sorcerer's Stone here, too. At the end of The Sorcerer's Stone, Harry awakens in the Hogwarts infirmary, filmed in the big-windowed Divinity School, on the ground floor of the Bodleian Library; Ron also recuperates here after being poisoned in The Half-Blood Prince.