6(1)In schemes under section 11 of the [1959 c. 25.] Highways Act 1959 made before 30th June 1961 references to traffic in Class VII set out in Schedule 4 to that Act are to be construed as including references to traffic in Classes X and XI set out in Schedule 4 to this Act.
(2)Sub-paragraph (1) above is without prejudice to the operation of sections 17(2)(a) and 23(3) of the [1978 c. 30.] Interpretation Act 1978 as respects the construction of references generally in such schemes as are referred to in that sub-paragraph, and without prejudice to the powers under section 14 of that Act and section 17(3) of this Act to amend such schemes and to amend Schedule 4 to this Act.