Thanks to Warner Brothers and their YouTube account, the entire webcast is now available on YouTube.
Note: The interviews actually start about 6 minutes in or so.
Watch the Warner Bros. Studio Tour London – The Making of Harry Potter – cast web chat on-demand here. Tom Felton, Julie Walters, Bonnie Wright, Nat Tena, Oliver Phelps, James Phelps, Mark Williams and Warwick Davis answer your questions from #wbstudiotour. Tickets are on sale now for the Studio Tour, opening 31st March 2012.