Proof of documents

47.–(1) In all proceedings in which any notice, order or other document required or authorized to be given or served under this Act has to be proved, the defendant shall be deemed to have received notice to produce it, and until the contrary is shown, that document and its due giving or service may be sufficiently proved by the production of what purports to be a copy, bearing a certificate under the hand of the person authorized to issue the original, stating that it was given or served on the date specified in the certificate. (2) The validity of any notice, order, other document or of its giving or service shall not be affected by an error, misdescription or irregularity which– (a) is not calculated to mislead; and (b) in fact does not mislead.