MIGRATION – two appeals from the Federal Circuit Court of Australia dismissing applications for judicial review – principles relevant to leave to raise a ground for the first time on appeal – whether the Immigration Assessment Authority engaged in irrational reasoning that amounted to legal unreasonableness – whether the primary judge erred in failing to find that the Authority misconceived its task under s 473DD of the Migration Act 1958 (Cth) – whether the primary judge erred in finding that there was only one fast track decision referred to the Authority for review and that the second appellant did not make his own protection claim – whether the Authority erred by not separately considering the two appellants’ protection claims – appeals allowed. I acted unled for the successful appellant in BTB18