While I’m not sure when the Warner Bros. Studio Tour in London will reopen, they did announce just before all the attractions began to shut down that they were adding a new addition to the Harry Potter themed portion of the tour. This new addition would bring a “Slytherin common room” to the tour for the first time. At the time of the announcement the plan was to add the Slytherin room to the tour just for a limited time, from April 3 to Sept. 6, 2020.
I’m not sure if this timeline will be revised once the attraction reopens or not, but if you are a fan of all things Harry Potter, then you’ll want to make your way there when it is ready to open.