room for residential purposesmeans a room, or a suite of rooms, which is not a dwelling-house or a flat and which is used by one or more persons to live and sleep and includes a room in a hostel, an hotel, a boarding house, a hall of residence or a residential home, whether or not the room is separated from or arranged in a cluster group with other rooms, but does not include a room in a hospital, or other similar establishment, used for patient accommodation and, for the purposes of this definition, a “cluster” is a group of rooms for residential purposes which is— (a) separated from the rest of the building in which it is situated by a door which is designed to be locked;