9.—(1) Where, in carrying out works under this Schedule—N.I.
(a)any road, bridge, culvert or embankment has been improved as a means of communication or otherwise in consequence of the carrying out of those works, such proportion of the cost of such works as ought fairly to be borne by the authority liable to maintain such road, bridge, culvert or embankment, or any portion thereof, shall be borne by that authority;
(b)any extra expenses are incurred by the Ministry by reason of the carrying out of additional works at the request or requirement of any authority pursuant to the principal agreement, such extra expenses shall be borne by the authority at whose request or requirement the additional works were carried out.
(2) Any dispute between the Ministry and an authority as to the amounts which, under the foregoing provisions of this paragraph, fall to be borne by that authority shall be referred to arbitrationF1. . . .
(3) For the purposes of this paragraph, “authority” means any person entitled or liable to maintain any road, bridge, culvert or embankment, or any part thereof, whether under any public general, local or privte statutory provision or under any order of court, scheme, deed or other instrument, or otherwise, and the provisions of any such statutory provision shall have effect subject to the foregoing provisions of this paragraph.