On and after the sixteenth day of May, nineteen hundred and fifty-seven, subsection (4) of section forty-seven of the Local Government (Scotland) Act, 1929 (which confers upon certain occupiers of industrial lands and heritages the right to recover in each year from the owner of such lands and heritages a sum equal to three times the owner's share of the rates payable in respect of such lands and heritages for that year) shall have effect as if for the words " said fifteenth day of May " there were substituted the words " fifteenth day of May, nineteen hundred and fifty-seven ".