S.3 For the purposes of Class S—
“camera”, except in paragraph S.1(a), includes its housing, pan and tilt mechanism, infra-red illuminator, receiver, mountings and brackets; and
“ground level” means the level of the surface of the ground immediately adjacent to the building to which the camera is attached or, where the level of the surface of the ground is not uniform, the level of the lowest part of the surface of the ground adjacent to it.