19Certificates
(1)The following certificates shall be evidence of the facts stated in them—
(a)a certificate signed by an officer of the Board as to any of the matters mentioned in section 14(1) of this Act;
(b)a certificate signed by an officer of the Board as to the total amount of gross wages paid by any person during the relevant period within the meaning of the last foregoing section to registered dock workers employed by him in any port; and
(c)a certificate signed by an officer of a licensing authority that a copy of a notice under subsection (7) of the last foregoing section of this Act is a true copy.
(2)A document purporting to be such a certificate as is mentioned in the foregoing subsection shall be taken to be such a certificate as aforesaid and received in evidence accordingly unless it is proved not to be such a certificate.