(1)Subject to the provisions of this and the last foregoing section, any notice, order or other document required or authorised to be served under this Act may be served either—
(a)by delivering it to the person on whom it is to be served, or
(b)by leaving it at the usual or last known place of abode of that person, or
(c)by sending it in a prepaid registered letter addressed to that person at his usual or last known place of abode, or
(d)in the case of an incorporated company or body, by delivering it to the secretary or clerk of the company or body at their registered or principal office or sending it in a prepaid registered letter addressed to the secretary or clerk of the company or body at that office, or
(e)if it is not practicable after reasonable enquiry to ascertain the name or address of an owner, lessee or occupier of land on whom it should be served, by addressing it to him by the description of " owner " or " lessee " or " occupier " of the premises (naming them) 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 can be delivered, by affixing it, or a copy of it, to some conspicuous part of the premises.
(2)This section shall not apply to the service under section nineteen of this Act of a copy of a closing order made under the proviso to subsection (1) of section seventeen of this Act or made under subsection (3) of that section, or to the service of a notice under section twenty-six or section thirty of this Act.