Sch 17 para 15
(1) Any notice or other document required or authorised to be served under this Schedule may be served on any person either by delivering it to him, or by leaving it at his proper address, or by post. (2) Any such document required or authorised to be served upon an incorporated company or body shall be duly served if it is served upon the secretary or clerk of the company or body. (3) For the purposes of this paragraph and of section 7 of the Interpretation Act 1978, the proper address of any person upon whom any such document is to be served is— (a) in the case of the secretary or clerk of any incorporated company or body, that of the registered or principal office of the company or body, and (b) in any other case, the last known address of the person to be served. (4) If it is not practicable after reasonable enquiry to ascertain the name or address of an owner or occupier of land on whom any such document is to be served, the document may be served by addressing it to him by the description of “ owner ” or “ occupier ” of the premises (describing 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.