(1)A notification under section 17 or 19 above which is required to be served on a person may be served by being delivered personally, or being sent by post in a registered letter or by the recorded delivery service.
(2)For the purposes of this section, and of section 7 of the [1978 c. 30.] Interpretation Act 1978 (which defines “service by post”) in its application to this section, a letter to a person other than a body corporate containing such a notification shall be deemed to be properly addressed if it is addressed to him at his address in the register or at his last known address if that address differs from his address in the register and it appears to the registrar that the notification is more likely to reach him at his last known address.
(3)A notification which is required to be served on a body corporate shall be duly served if it is served on the secretary or clerk of that body.
(4)For the purposes of this section, and of section 7 of the [1978 c. 30.] Interpretation Act 1978 in its application to this section, the proper address of a person, in the case of a body corporate or the secretary or clerk of a body corporate, shall be its address in the list or the address of its registered or principal office if that address differs from its address in the list and it appears to the registrar that the notification is more likely to reach the body corporate or its secretary or clerk there.