(2) If, for the purpose of executing any works in, on, under or over any land purchased, held,  appropriated or used under this Order, the undertaker requires the removal of any apparatus placed  in that land, it must give to National Grid no less than 56 days’ advance written notice of that  requirement, together with a plan of the work proposed, and of the proposed position of the  alternative apparatus to be provided or constructed and in that case (or if in consequence of the  exercise of any of the powers conferred by this Order National Grid reasonably needs to remove  any of its apparatus) the undertaker must, subject to sub-paragraph (3), afford to National Grid to  its satisfaction (taking into account paragraph 73(1) below) the necessary facilities and rights—  (3) If alternative apparatus or any part of such apparatus is to be constructed elsewhere than in  other land of or land secured by the undertaker, or the undertaker is unable to afford such facilities  and rights as are mentioned in sub-paragraph (2), in the land in which the alternative apparatus or  part of such apparatus is to be constructed, National Grid must, on receipt of a written notice to  that effect from the undertaker, take such steps as are reasonable in the circumstances in an  endeavour to obtain the necessary facilities and rights in the land in which the alternative  apparatus is to be constructed save that this obligation does not extend to the requirement for  National Grid to use its compulsory purchase powers to this end unless it elects to so do.  (4) Any alternative apparatus to be constructed in land of or land secured by the undertaker  under this Part of this Schedule must be constructed in such manner and in such line or situation as  may be agreed between National Grid and the undertaker.  (5) National Grid must, after the alternative apparatus to be provided or constructed has been  agreed, and subject to the prior grant to National Grid of any such facilities and rights as are  referred to in sub-paragraph (2) or (3), proceed without unnecessary delay to construct and bring  into operation the alternative apparatus and subsequently to remove any apparatus required by the  undertaker to be removed under the provisions of this Part of this Schedule.  73. —(1) Where, in accordance with the provisions of this Part of this Schedule, the undertaker  affords to or secures for National Grid facilities and rights in land for the construction, use,  maintenance and protection of alternative apparatus in substitution for apparatus to be removed,  those facilities and rights must be granted upon such terms and conditions as may be agreed  between the undertaker and National Grid and must be no less favourable on the whole to National  Grid than the facilities and rights enjoyed by it in respect of the apparatus to be removed unless  otherwise agreed by National Grid.  (2) If the facilities and rights to be afforded by the undertaker and agreed with National Grid  under sub–paragraph (1) in respect of any alternative apparatus, and the terms and conditions  subject to which those facilities and rights are to be granted, are less favourable on the whole to  National Grid than the facilities and rights enjoyed by it in respect of the apparatus to be removed  and the terms and conditions to which those facilities and rights are subject in the matter will be  referred to arbitration in accordance with paragraph 80 (arbitration) of this Part of this Schedule  and the arbitrator must make such provision for the payment of compensation by the undertaker to  National Grid as appears to the arbitrator to be reasonable having regard to all the circumstances  of the particular case. In respect of the appointment of an arbitrator under this sub-paragraph (2),  article 42(3) (arbitration) of the Order must apply.  74. —(1) Not less than 56 days before the commencement of any specified works, the removal of  which has not been required by the undertaker under paragraph (72(2)) or otherwise and to which  sub-paragraphs (2)(a) or (2)(b) applies the undertaker must submit to National Grid a plan of the  works to be executed and seek from National Grid details of the underground extent of its  electricity tower foundations.  96 Retained apparatus  Facilities and rights for alternative apparatus  (a) for the construction of alternative apparatus in other land of or land secured by the  undertaker; and  (b) subsequently for the maintenance of that apparatus. 