3If a person on whom a notice is served under paragraph 1 fails to show cause to the authority's satisfaction, they may refuse to register him or may cancel his registration, as the case may be, and—
(a)shall forthwith give notice to him of their decision in the matter; and
(b)shall, if so required by him within 14 days from the date of their decision, give to him within 48 hours after receiving the requirement, a statement of the grounds of the decision.