20Service of notices, etc.
(1)Any notice or other document required or authorised to be served or given in writing under this Act may be served or given either—
(a)by delivering it to the person on whom it is to be served or to whom it is to be given; or
(b)by leaving it at the usual or last known place of abode or business of that person, or, in a case where an address for service has been given by that person, at that address; or
(c)by sending it by ordinary post addressed to that person at his usual or last known place of abode or business, or, in a case where an address for service has been given by that person, at that address; or
(d)in the case of a company or body incorporated in England or Wales, by delivering it to the secretary or clerk of the company or body at their registered or principal office, or sending it by ordinary post addressed to the secretary or clerk of the company or body at that office.
(2)If the name or address of any person on whom any notice or other document required or authorised to be served under the provisions of this Act cannot after reasonable enquiry be ascertained, the document may be given or served by either—
(a)leaving it in the hands of a person who appears to be the owner of, resident in or employed in; or
(b)leaving it conspicuously affixed to some part of,
the premises being used or to be used for trading regulated under the provisions of this Act.