A first embodiment provides a manually operable castor assembly (4) for a hospital bed, including a wheel unit (4) fittable to a bed frame (6) and provided with a lock actuator (5). A sensor unit (11, 12) is provided with a trigger element (12) and a sensor element(11), the trigger element being located on the manually operable brake actuator (5) and the sensor element (11) being located on the wheel unit (4). Another embodiment provides a manually operable safety side panel assembly (1,2) including a hinge assembly (3) coupled to the panel element and attachable to a bed frame, and a sensor unit including a trigger element (18) and a sensor element (25), the trigger element (11) being located on the manually operable actuator and the sensor element being located on a part of the side panel or hinge assembly. Monitoring apparatus monitors the manually operable bed safety device and including a control unit coupled to the sensor unit and an indicator unit controllable by the control unit and operable to give an indication of the state of the device.