s 17 Service of notices.
Any notice required or authorised by or under this Act to be served on any person may be served either— (a) by delivering it to that person; or (b) by leaving it or sending it in a registered letter to him at his usual or last known residence or place of business; or (c) in the case of an incorporated company or body, by delivering it to their clerk or secretary at their registered or principal office, or by sending it in a registered letter addressed to him at that office; or (d) in the case of a notice to be served on the owner, lessee or occupier of land, if it is not practicable after reasonable inquiry to ascertain his name or address, addressing it to him by the description “owner,” “lessee” or “occupier” of the land (describing it) to which it relates, and by delivering it to some person on the premises or, if there is no person on the premises to whom it may be delivered, by affixing it, or a copy of it, to some conspicuous part of the premises.