Parts II and IV of, and Schedules 1 and 2 to, the Criminal Appeal Act as modified by the provisions of this Act shall have effect for the purposes of appeals to the Court of Appeal against convictions before or sentences passed by the Crown Court and for the purposes of references to the Court of Appeal under that Act, and the Court of Appeal shall have full power to determine, in accordance with that Act, any question necessary to be determined for the purpose of doing justice in the case before the court.