This is useful thanks. I'm not a fan of spiral staircases at the best of times but I would hate to climb those at night! Surely someone would have to be descending super stealthily to not rouse everyone?! So NQ and siblings were on the mezzanine floor? And parents on the ground floor? And one of the large windows was open in the morning? Is the balcony totally open - assume there must be a door I can't see? Sliding?