3Where, by virtue of paragraph 21 or paragraph 22 of Schedule 2 to the 1976 Act (general rules for determining amount of consideration),—
(a)consideration is brought into account without any discount for postponed payment or without regard to any risk of irrecoverability, or
(b)consideration is determined without taking account of any contingent liability,
no further assessment to tax shall be raised by reason of anything occurring on or after 19th March 1985, but relief by way of discharge or repayment of tax or otherwise shall continue to be available on and after that date under sub-paragraph (2) of the paragraph in question.