Pt. 6 omitted (with effect in relation to accounting periods beginning on or after 1.1.2017 in accordance with Sch. 10 para. 22 of the amending Act) by virtue of Finance Act 2016 (c. 24), Sch. 10 para. 15; and ss. 257, 257 so far as continuing to have effect are amended (with effect in accordance with Sch. 15 para. 44 of the amending Act) by Finance (No. 2) Act 2017 (c. 32), Sch. 15 paras. 41, 42