A surveillance agency to whom an interception warrant is issued, or any other lawful interception authority is granted, may, for the purpose of requiring assistance in the execution of the warrant or lawful authority, show to either or both of the persons referred to in subsection (2),—
(a)
in the case of an interception warrant issued to an intelligence and security agency, a copy of the relevant parts of the warrant; or
(b)
in any other case, a copy of the warrant or evidence of lawful authority.