Interest on tax
9(1)For the purposes of section 86(3) of this Act, the tax charged by any assessment by virtue of section 15(2) of the [1967 c. 54.] Finance Act 1967 (increase of surtax rates for 1965-66) shall be treated as if it had been charged by an assessment separately made.
(2)For the purposes of section 88 of this Act the due date for payment of so much of any surtax for the year 1965-66 as is attributable to subsection (1) of the said section 15 shall be taken to be 1st September 1967, instead of 1st January 1967.