3For the purpose of totals of values in the county of London, any amendment made in a valuation list in force on the first day of October, nineteen hundred and twenty-nine, on the ground that a hereditament was or was not on that date an agricultural, industrial, or freight transport hereditament shall, if made by means of a special list prepared in accordance with the Hating and Valuation (Apportionment) Act, 1928, or by means of a provisional list sent to the assessment committee before the first day of October, nineteen hundred and thirty, or sent to them in compliance with a requisition served on the rating authority before that date, have effect notwithstanding anything in subsection (11) of section forty-seven of the Valuation (Metropolis) Act, 1869, as if it had been made by a supplemental fist coming into force on the sixth day of April, nineteen hundred and thirty.