Despite anything else in this Division, the powers of an inspector under this Division in relation to entering a place are not exercisable in relation to any part of a place that is used only for residential purposes except--
(a) with the consent of the person with management or control of the place, or
(b) under the authority conferred by a search warrant, or
(c) for the purpose only of gaining access to a suspected workplace, but only--(i) if the inspector reasonably believes that no reasonable alternative access is available, and(ii) at a reasonable time having regard to the times at which the inspector believes work is being carried out at the place to which access is sought.