The Kudo family went on vacation to Britain.
After visiting Baker Street, Yukiko dragged Shinichi along to see the Harry Potter filming locations. "Didn't we already finish sightseeing?" "Shin-chan, Britain has more than just Sherlock Holmes. It also has Hogwarts." While visiting Diagon Alley, Yukiko accidentally walked into the Leaky Cauldron (it seems you can't go inside the one at the filming location), and the whole group ended up packed off to the world of Harry Potter.
"Mom, where are we?" "This is Diagon Alley, Shin-chan. Let's go buy you a wand."
