s 57 Decision to be final and conclusive
57. Except as expressly provided in this Act —(a) where no valid notice of appeal has been lodged within the time limits under section 51 against the decision of the Comptroller on any matter referred to in section 49; (b) where such notice has been lodged but it has been withdrawn before the decision has been determined on appeal; (c) where an agreement (whether in writing or otherwise) has been reached on the decision made between the Comptroller and the person who lodged the notice and the Comptroller has in consequence varied the decision in writing; or (d) where the decision has been determined on appeal, the decision as made, varied in consequence of the agreement or determined on appeal is final and conclusive for the purposes of this Act.