Subject to the provisions of this section, the Court of Appeal—
Where apart from this subsection—
the Court of Appeal may dismiss the appeal if they are of opinion that, but for the insanity of the accused, the proper verdict would have been that he was guilty of an offence other than the offence charged.
Where an appeal under section 12 of this Act is allowed, the following provisions apply:—
The Court of Appeal shall not by virtue of subsection (4)(a) above sentence any person to death; but where under that paragraph they substitute a verdict of guilty of an offence for which apart from this subsection they would be required to sentence the appellant to death, their sentence shall (whatever the circumstances) be one of imprisonment for life.
An order of the Court of Appeal allowing an appeal in accordance with this section shall operate as a direction to the court of trial to amend the record to conform with the order.