Where, on the trial of a person by court-martial, the court is satisfied, as respects the charge or any of the charges on which he is being tried, that the accused did the act or made the omission charged against him as the offence but that at the time of that act or omission he was insane, the court shall find that the accused was not guilty of that offence by reason of insanity.

No finding under subsection (1) above shall be made except on the written or oral evidence of two or more registered medical practitioners at least one of whom is duly approved.