16Trade unions
(1)If a trade union entered in the list of trade unions maintained under the [1974 c. 52.] Trade Union and Labour Relations Act 1974 was formed after 30th September 1971, it shall be treated as having been a registered trade union within the meaning of section 338 of the Taxes Act (exemption for trade unions) at all times between its formation and its entry in that list.
(2)If a trade union was a registered trade union on 30th September 1971, it shall be treated for the purposes of the said section 338 as having remained a registered trade union so long as it remained a trade union and was not entered in the said list.