 The power may be exercised only to the extent that it is reasonably required for that purpose; and only if the officer has reasonable grounds for believing that the person whom he is seeking is on the premises.In relation to premises consisting of two or more separate dwellings, the power is limited to entering and searching any parts of the premises which the occupiers of any dwelling comprised in the premises use in common with the occupiers of any other such dwelling; and any such dwelling in which the officer has reasonable grounds for believing that the person whom he is seeking may be.An authorised officer may enter and search any premises for the purpose of executing a warrant of distress issued under section 76 of the Magistrates' Courts Act for default in paying a sum adjudged to be paid by a conviction.