If—
(a) the addressee has any objection to producing a document identified in the subpoena or to its being inspected by any one or more of the parties to the proceeding; or
(b) a person having a sufficient interest, other than a party, has any objection to the production of a document identified in the subpoena or to its being inspected by any one or more of the parties to the proceeding—
that person must notify the registrar in writing of that objection and state the grounds of that objection before the day specified in the subpoena.