Prospective
18U.K.R may not be notified of any assessment under paragraph 16(2) or of any increase in an assessment under paragraph 4(2) of Schedule 10 in respect of an amount after the end of the period of 2 years beginning with—
(a)the day after the last day of the accounting period by reference to which P was liable to pay the amount, or, if later,
(b)the day on which a court or tribunal finally determines that P is liable to pay the amount.