appears to the arbitrator to be reasonable having regard to all the circumstances of the particular  case.  89. —(1) Not less than 28 days before starting the execution of any works in, on or under any  land purchased, held, appropriated or used under this Order that are near to, or will or may affect,  any apparatus the removal of which has not been required by the undertaker under paragraph 87,  the undertaker must submit to the utility undertaker in question a plan, section and description of  the works to be executed.  (2) Those works must be executed only in accordance with the plan, section and description  submitted under sub-paragraph (1) and in accordance with such reasonable requirements as may  be made in accordance with sub-paragraph (3) by the utility undertaker for the alteration or  otherwise for the protection of the apparatus, or for securing access to it, and the utility undertaker  is entitled to watch and inspect the execution of those works.  (3) Any requirements made by a utility undertaker under sub-paragraph (2) must be made within  a period of 28 days beginning with the date on which a plan, section and description under sub- paragraph (1) are submitted to it.  (4) If a utility undertaker in accordance with sub-paragraph (3) and in consequence of the works  proposed by the undertaker, reasonably requires the removal of any apparatus and gives written  notice to the undertaker of that requirement, paragraphs 82 to 88 apply as if the removal of the  apparatus had been required by the undertaker under paragraph 87(2).  (5) Nothing in this paragraph precludes the undertaker from submitting at any time or from time  to time, but in no case less than 28 days before commencing the execution of any works, a new  plan, section and description instead of the plan, section and description previously submitted, and  having done so the provisions of this paragraph apply to and in respect of the new plan, section  and description.  (6) The undertaker is not required to comply with sub-paragraph (1) in a case of emergency but  in that case it must give to the utility undertaker in question notice as soon as is reasonably  practicable and a plan, section and description of those works as soon as reasonably practicable  subsequently and must comply with sub-paragraph (2) in so far as is reasonably practicable in the  circumstances.  90. —(1) Subject to the following provisions of this paragraph, the undertaker must repay to a  utility undertaker the reasonable expenses incurred by that utility undertaker in, or in connection  with, the inspection, removal, alteration or protection of any apparatus or the construction of any  new apparatus which may be required in consequence of the execution of any such works as are  referred to in paragraph 87(2).  (2) There is to be deducted from any sum payable under sub-paragraph (1) the value of any  apparatus removed under the provisions of this Part of this Schedule, that value being calculated  after removal.  (3) If in accordance with the provisions of this Part of this Schedule—  and the placing of apparatus of that type or capacity or of those dimensions or the placing of  apparatus at that depth, as the case may be, is not agreed by the undertaker or, in default of  agreement, is not determined by arbitration in accordance with article 42(3) to be necessary, then,  if such placing involves cost in the construction of works under this part of this Schedule  exceeding that which would have been involved if the apparatus placed had been of the existing  type, capacity or dimensions, or at the existing depth, as the case may be, the amount which apart  from this sub-paragraph would be payable to the utility undertaker in question by virtue of sub- paragraph (1) is to be reduced by the amount of that excess.  (4) For the purposes of sub-paragraph (3)—  103 (b) apparatus (whether existing apparatus or apparatus substituted for existing apparatus) is  placed at a depth greater than the depth at which the existing apparatus was,  (a) apparatus of better type, of greater capacity or of greater dimensions is placed in  substitution for existing apparatus of worse type, of smaller capacity or of smaller  dimensions; or 