The price payable under this section for water drawn at any time after the first day of October, nineteen hundred and sixty-one, shall be one shilling and sixpence a thousand gallons or such other price as may from time to time be mutually agreed upon between the said Corporation and the Council of any such suburban boroughs or, failing agreement, as may from time to time be fixed by arbitration under the Arbitration Act 1908 of two indifferent persons, one to be appointed by the said Corporation and one by such Council or Councils, and an umpire to be appointed by the arbitrators or by the Supreme Court in manner provided by the Arbitration Act 1908.”