6E+WIf any question arises under this Schedule—
(a)as to whether anything done or proposed to be done interferes or will interfere as mentioned in paragraph 3 or 4 above;
(b)as to whether any consent for the purposes of this Schedule is being unreasonably withheld; or
(c)as to whether any condition subject to which any such consent has been given was reasonable,
that question shall be referred to a single arbitrator to be agreed between the parties or, failing such an agreement, to be appointed by the President of the Institution of Civil Engineers.