In section 53(2) (rating in Scotland), for the words from " entered " to the end there shall be substituted the words " apportioned by the Assessor of Public Undertakings (Scotland) among rating areas in such manner as the Secretary of State may by order determine and the Assessor shall direct the local assessor under section 5 of the Local Government (Scotland) Act 1975 to enter the values as so apportioned in the valuation roll ".