5.—(1) Where notice has been served upon any person under Article 49 the Department may, with the consent of that person, do on his behalf anything necessary for complying with the requirements of the notice.
(2) Where any such person, within 21 days after the service upon him of the notice, signifies in writing to the Department his assent to the doing by the Department on his behalf of any such thing as aforesaid, such person shall not be liable to prosecution for an offence under paragraph 6.