3.—(1) The Secretary of State may appoint a person to exercise any or all of his functions in relation to—
(a)applications of all or any of the kinds referred to in paragraphs (1) and (2) of regulation 2; or
(b)one or more particular applications of any of those kinds.
(2) An appointment under paragraph (1) must be in writing.
(3) The Secretary of State may at any time, by giving notice in writing to a person appointed under paragraph (1) (an “appointed person”)—
(a)revoke the appointment generally;
(b)revoke the appointment insofar as it relates to a particular application which has not been determined by the appointed person before that time; or
(c)revoke the authority of the appointed person to exercise a particular function in relation to an application.
(4) A notice under paragraph (3) shall not affect the validity of anything done by the appointed person before the notice is given.