21.—(1) The Company and Heathrow Airport Limited may enter into and carry into effect agreements with respect to the construction, maintenance, use and operation of the authorised works or any part thereof and as to any other matters incidental or subsidiary thereto or consequential thereon, including the defraying of or making of contributions towards costs incurred by either party to the agreement.
(2) Any such agreement may provide for the exercise by Heathrow Airport Limited, or the Company and Heathrow Airport Limited jointly, of all or any of the powers of the Company (whether under this Order or under any other enactment) in respect of the authorised works or any part thereof and for the transfer to and vesting in Heathrow Airport Limited, or the Company and Heathrow Airport Limited jointly, of those works or any part thereof together with the rights and obligations of the Company in relation thereto.
(3) Any such agreement may also provide for the use by the Company, for the purpose of the railway comprised in the authorised works, of any works or facilities constructed within the limits of deviation or the areas described in Schedule 2 to this Order under any enactment authorising an extension of the railway authorised by the Heathrow Express Railway Act 1991(1).
(4) The exercise by Heathrow Airport Limited or the Company and Heathrow Airport Limited jointly, of any of the powers of this Order shall be subject to all statutory and contractual provisions in relation thereto as would apply if those powers were exercised by the Company alone and accordingly those provisions with any necessary modifications shall apply to the exercise of such powers by Heathrow Airport Limited, or by the Company and Heathrow Airport Limited jointly.
(5) In this article references to Heathrow Airport Limited include references to any subsidiary (within the meaning of section 736 of the Companies Act 1985(2)) of Heathrow Airport Limited.
22. The provisions of Schedule 4 to this Order shall have effect.
23. If the powers of the Company under this Order to construct the authorised works or any part thereof are transferred to another person by virtue of an agreement under article 21 above then, except as may be otherwise provided in such agreement or Order, the provisions of Schedule 5 to this Order shall apply for the protection of the Company.
24. The provisions of Schedule 6 to this Order shall have effect.
25. The provisions of Schedule 7 to this Order shall have effect.
26. The Company shall, as soon as practicable after the making of this Order, submit copies of the book of reference, the deposited sections and the deposited plans to the Secretary of State for certification that they are true copies of, respectively, the book of reference, sections and plans referred to in this Order, and a document so certified shall be admissible in any proceedings as evidence of the contents of the document of which it is a copy.
27.—(1) A notice or other document required or authorised to be served for the purposes of this Order may be served by post.
(2) Where the person on whom a notice or other document to be served for the purposes of this Order is a body corporate, the notice or document is duly served if it is served on the secretary or clerk of that body.
(3) For the purposes of section 7 of the Interpretation Act 1978(3) as it applies for the purposes of this article, the proper address of any person in relation to the service on him of a notice or document under paragraph (1) above is, if he has given an address for service, that address, and otherwise—
(a)in the case of the secretary or clerk of a body corporate, the registered or principal office of that body, and
(b)in any other case, his last known address at the time of service.
(4) Where for the purposes of this Order a notice or other document is required or authorised to be served on a person as having any interest in, or as the occupier of, land and his name or address cannot be ascertained after reasonable enquiry, the notice may be served by—
(a)addressing it to him by name or by the description of “owner”, or as the case may be “occupier”, of the land (describing it), and
(b)either leaving it in the hands of a person who is or appears to be resident or employed on the land or leaving it conspicuously affixed to some building or object on or near the land.
(5) This article shall not be taken to exclude the employment of any method of service not expressly provided for by it.
28. Compensation shall not be payable in respect of the same matter both under this Order and under any other enactment, any contract or any rule of law.
29. Any difference under any provision of this Order (other than a difference which falls to be determined by the tribunal) shall be referred to and settled by a single arbitrator to be agreed between the parties or, failing agreement, to be appointed on the application of either party (after notice in writing to the other) by the President of the Institution of Civil Engineers.