In relation to gains accruing on disposals after 5th April 1974 section 112 of the M1Finance Act 1972 (reduction of tax liability on certain disposals of shares in unit trusts, investment trusts and funds in court) shall have effect as if for the references in paragraphs (b) and (c) of subsection (3) to 15 per cent, there were substituted references to 16 ½ per cent.