Every document purporting to be an instrument made or issued by the Commission and to be duly sealed with the seal of the Commission or to be signed by the secretary or any person authorised to act in that behalf shall be received in evidence and, unless the contrary is proved, shall be deemed to be an instrument made or issued by the Commission.

Prima facie evidence of any such instrument may in any legal proceedings be given by the production of a document purporting to be certified by or on behalf of the secretary of the Commission to be a true copy of the instrument.