The first time we went to the Warner Brothers Harry Potter Studio Tour was in 2015, just after they had added the Hogwarts Express and Kings Cross set to the tour. At the end of November 2019 we made a return visit, mainly to see how different it was dressed for Christmas and with snow.
I had expectations that Diagon Alley would be (or could be) rather festive, but in the end it was no different to how it is normally. Well there were some footprints in the snow and the special effects about how they were created, but that was less Diagon Alley and more Hogsmead.
Diagon Alley is a cobblestoned wizarding alley and shopping area located in London, England behind a pub called the Leaky Cauldron. Inside the alley is an assortment of restaurants, shops, and other sights.