His purely technical argument was that, according to the naked law, once a decision has been published, nothing exists to revive the powers of an adjudicator to correct any errors. The referee has left the pitch, so too the players. Even the crowd has gone home. He can't run back on the pitch and admit he wrote down the wrong score. But a judge can correct at any time up to the point when he later draws up his formal order.
Arbitrators make slip-ups too.
In one case, for instance, an arbitrator awarded all the money to x but meant y, but corrected it using the slip rule in the Arbitration Act. You might argue that if parliament had intended a similar slip rule in adjudication, it would have been put it in. Since it hasn't, the decision cannot be corrected. Provided the parties do not expressly ban a slip rule in the contract, an adjudicator can correct an admitted accidental slip or omission. This is not an opportunity to have second thoughts to produce a revised decision or award.