Where, upon the hearing of an appeal under this Act against a conviction or a prescribed acquittal by a court martial or a Defence Force magistrate, the Tribunal thinks it necessary or expedient in the interests of justice to do so, the Tribunal may direct such steps to be taken as are necessary to obtain from the person who was the judge advocate of the court martial or from the Defence Force magistrate, a report giving his or her opinion upon the case, or upon a point arising in the case, or containing a statement as to any facts the ascertainment of which appears to the Tribunal to be material for the purpose of the determination of the appeal.