50   Evidence

A certificate signed by the Director-General certifying any one or more of the following:

(a)  that a written notice, order or direction purporting to be given under this Act, and a copy of which is set out or annexed to the certificate, was given on a day specified in the certificate,

(b)  that a person was, at a time or during a period specified in the certificate, a landholder,

(c)  that a person was, at a time or during a period specified in the certificate, an authorised officer,

(d)  that any instrument made under this Act was, at a time or during a period specified in the certificate, in force,

is admissible in any proceedings under this Act and is prima facie evidence of the matters so specified.