(5) The Agency must give to the undertaker reasonable notice of any such claim or demand and  no settlement or compromise may be made without the agreement of the undertaker, such  agreement not to be unreasonably withheld or delayed.  (6) The fact that any work or thing has been executed or done by the undertaker in accordance  with a plan approved by the Agency, or to its satisfaction, or in accordance with any directions or  award of an arbitrator, does not relieve the undertaker from any liability under the provisions of  this Part of this Schedule.  43.  Any dispute arising between the undertaker and the Agency under this Part of this Schedule  must, if the parties agree, be determined by arbitration under article 42(3) (arbitration) of this  Order, but otherwise must be determined by the Secretary of State for Environment, Food and  Rural Affairs or its successor on a reference to them by the undertaker or the Agency, after notice  in writing by one to the other.  44.  The following provisions of this Part of this Schedule have effect, unless otherwise agreed in  writing between the undertaker and Network Rail and, in the case of paragraph 58, any other  person on whom rights or obligations are conferred by that paragraph.  45.  In this Part of this Schedule—  “construction” includes execution, placing, alteration and reconstruction and “construct” and  “constructed” have corresponding meanings;  “the engineer” means an engineer appointed by Network Rail for the purposes of this Order;  “network licence” means the network licence, as the same is amended from time to time,  granted to Network Rail Infrastructure Limited by the Secretary of State in exercise of his  powers under section 8 (licenses) of the Railways Act l993( a );  “Network Rail” means Network Rail Infrastructure Limited (company number 0204587,  whose registered office is at 1 Eversholt Street, London, NW1 2DN) and any associated  company of Network Rail Infrastructure Limited which holds property for railway purposes,  and for the purpose of this definition “associated company” means any company which is  (within the meaning of section 1159 (meaning of “subsidiary” etc) of the Companies Act  2006( b )) the holding company of Network Rail Infrastructure Limited, a subsidiary of  Network Rail Infrastructure Limited or another subsidiary of the holding company of Network  Rail Infrastructure Limited;  “plans” includes sections, designs, design data, software, drawings, specifications, soil reports,  calculations, descriptions (including descriptions of methods of construction), staging  proposals, programmes and details of the extent, timing and duration of any proposed  occupation of railway property;  “protective works” means any works specified by the engineer under paragraph 48(4);  “railway operational procedures” means procedures specified under any access agreement (as  defined in the Railways Act 1993) or station lease;  ( a ) 1993 c.43.  ( b ) 2006 c.46  86 (a) contractual liabilities;  (b) tortious liabilities (including liabilities for negligence or nuisance);  (c) liabilities to pay statutory compensation or for breach of statutory duty; and  (d) liabilities to pay statutory penalties imposed on the basis of strict liability (but does not  include liabilities to pay other statutory penalties).  PART 5  FOR THE PROTECTION OF RAILWAY INTERESTS 