Proof of instruments

Every document purporting to be an instrument made or issued by any authority or person in pursuance of any provision contained in, or having effect under, regulations made by virtue of this Act, and to be signed by or on behalf of the authority or person, shall be received in evidence and shall, until the contrary is proved, be deemed to be an instrument made or issued by that authority or person; and prima facie evidence of any such instrument may, in any legal proceedings, including arbitrations, be given by production of a document purporting to be certified to be a true copy of an instrument by, or on behalf of the authority or person having power to make or issue the