(1)Where in pursuance of any enactment, statutory order or agreement any sum is required to be calculated according to the gross annual valuation of any area or is required to be apportioned and allocated among local authorities or other bodies according to the gross annual valuation of any two or more areas, such calculation or such apportionment and allocation, as the case may be, shall, on and after the sixteenth day of May, nineteen hundred and sixty-one, be made according to the net annual valuation of the area or areas in question.
(2)Subsection (2) of section two hundred and eighteen of the Act of 1947 (which subsection contains provisions relating to the apportionment of expenditure among local authorities) shall on and after the date mentioned in the foregoing subsection have effect as if for the words " gross annual valuations " appearing therein there were substituted the words " net annual valuations ".