24.—(1) Every self-employed person liable to pay contributions under these Regulations shall immediately inform the Board in writing of any change of his address, except that a self-employed person who changes his residential address shall be deemed to have informed the Board of such change in compliance with this paragraph upon his making a report thereof under section 8 of the National Registration Act (Cap. 201).
(2) Where any person has changed his address without informing the Board as required under paragraph (1), any notice or document given or served on him by posting the notice or document or a copy thereof to him at his last known address shall be deemed to have been duly given or served and shall be conclusive evidence of the fact of service.