20. Any person aggrieved by an order of the Authority under section 11 or section 19 may, within sixty days of the receipt of such order, appeal against it to the ²[High Court Division] on any of the following grounds, namely:- (a) that the order is contrary to law or to some usage having the force of law; (b) that the order has failed to determine some material issue of law or usage having the force of law; (c) that there has been a substantial error or defect in following the procedure provided in this Ordinance which may possibly have produced error or defect in the order upon the merits.