Sch 1 para 8
(1) The application of the seal of the Authority to a statutory instrument shall be authenticated by the signature of the chairman or by some other person who has been authorised by the Authority to act for that purpose. (2) A document purporting to be duly executed under the seal of the Authority, or signed on its behalf, shall be received in evidence and, unless the contrary is proved, be taken to be so executed or signed.