(1)Where, on the thirty-first day of March, nineteen hundred and forty-eight, the whole or any part of a hereditament which is shown in any valuation list in force at the said date as a railway hereditament within the meaning of the Railways (Valuation for Rating) Act, 1930, or as a transport hereditament within the meaning of that Act as applied by a scheme under section ninety-two of the London Passenger Transport Act, 1933, is in the occupation of some person other than the British Transport Commission, such amendments may be made of the valuation list (by way of proposal under Part III of this Act, of proposal under the Rating and Valuation Act, 1925, or of provisional or supplemental list, according as may be appropriate) as are necessary to secure that that hereditament or, as the case may be, that part thereof, appears as a separate hereditament in the list, as if it had not been shown in the valuation list as being, or forming part of, a railway hereditament or a transport hereditament.
(2)For the purpose of the liability of any person (other than the British Transport Commission) to rates, an amendment made under this section shall, in relation to any rate (including any rate for a period which has already elapsed when the amendment is made), have effect as from the beginning of the quinquennial period under the Railways (Valuation for Rating) Act, 1930 (or, as the case may be, under that Act as applied by the London Passenger Transport (Valuation for Rating) Scheme, 1935) current at the date of the passing of this Act or as from the date on which the hereditament ceased to be in the occupation of the British Transport Commission or, as the case may be, the relevant body specified in the Third Schedule to the Transport Act, 1947, whichever is the later date ; and the amount underpaid shall be paid and may be recovered as if it were arrears of the rate.