“(1) If an officer of a local housing authority enters premises under section (

(a) produce evidence of the officer's identity and authority to that occupier or (if there is more than one) to at least one of them, and

(b) if the entry takes place otherwise than in the course of a routine inspection, provide to that occupier or (if there is more than one) to at least one of them a document that—

(i) sets out why the entry is necessary, and