Sch 3 para 7
(1) In the case of an all-premises warrant, premises that are not specified in the warrant may be entered and searched only if a relevant enforcement officer of the appropriate grade has authorised them to be entered. (2) An authorisation under sub-paragraph (1) must be in writing. (3) In this paragraph— “ all-premises warrant ” has the meaning given by section 39(3); “ relevant enforcement officer of the appropriate grade ” means— a senior officer (see section 13(7)), or in the case of a search warrant issued on the application of an officer of a local authority, a person designated by the local authority for the purposes of this paragraph.