143. The undertaker must exercise the powers conferred by article 22 (protective work to buildings) so as not to obstruct or render less convenient the access to any apparatus without the written consent of UU Water (such consent not to be unreasonably withheld or delayed) and if by reason of the exercise of those powers any damage to any apparatus (other than apparatus the repair of which is not reasonably necessary in the view of its intended removal or abandonment) or property of UU Water or any interruption in the supply of water and the provision of sewerage services by UU Water, as the case may be, is caused, the undertaker must bear and pay on demand the cost reasonably incurred and documented by UU Water in making good such damage or restoring the supply; and, shall pay compensation to UU Water for any loss sustained by reason of any such damage or interruption.