Nothing in paragraph (a) of section 20(2) of this Act affects the validity or prevents the renewal of any pilotage certificate in force immediately before 4th July 1980 (the commencement date of paragraph 8(1)(b) of Schedule 2 to the [1979 c. 39.] Merchant Shipping Act 1979) in respect of a ship which is not registered under the law of a member State of the Economic Community.