2. An appointment must be in writing and —
(a)may relate to any particular appeal or matter specified in the appointment or to appeals or matters of a description so specified;
(b)shall provide for the appointed person to determine the appeal or matter specified in the appointment;
(c)may provide for any function to which it relates to be exercisable by the appointed person either unconditionally or subject to the fulfilment of such conditions as may be specified in the appointment; and
(d)may, by notice in writing given to the appointed person, be revoked at any time by the Department in respect of any appeal or matter which has not been determined by the appointed person before that time.