The Registrar-General shall have and use a seal of office bearing the
impression of the Royal Arms of England and the words "Registrar-General South
Australia"; and every instrument bearing such seal, and purporting to be
issued by the Registrar-General, or by a Deputy Registrar-General or a
delegate referred to in section 17, shall be received in evidence, and
shall be deemed to be issued by or under the direction of the
Registrar-General without further proof, unless the contrary be shown.