12(1)If any person is aggrieved by an order which has taken effect and desires to question its validity on the ground that it is not within the powers of section 53 or 54 or that any of the requirements of this Schedule have not been complied with in relation to it, he may within 42 days from the date of publication of the notice under paragraph 11 make an application to the High Court under this paragraph.
(2)On any such application the High Court may, if satisfied that the order is not within those powers or that the interests of the applicant have been substantially prejudiced by a failure to comply with those requirements, quash the order, or any provision of the order, either generally or in so far as it affects the interests of the applicant.
(3)Except as provided by this paragraph, the validity of an order shall not be questioned in any legal proceedings whatsoever.