Where a designation applies this paragraph to any person, section 21 of the 1984 Act (access and copying) shall have effect in relation to anything seized in the relevant police area by a constable F1or by a person authorised to accompany him under section 16(2) of that Act as if the references to a constable in subsections (3), (4) and (5) of section 21 (supervision of access and photographing of seized items) included references to a person to whom this paragraph applies.