12The repeals made by the principal Act shall not affect proceedings for any offence punishable under section 505 of the [1952 c. 10.] Income Tax Act 1952 and committed before the repeal of the said section 505 by the [1968 c. 60.] Theft Act 1968, or, in Northern Ireland, by the [1969 c. 16 (N.I.).] Theft Act (Northern Ireland) 1969.