51. (1) The Authority may appoint in writing such persons or classes of person as he or she considers appropriate to be authorised officers for the exercise of all or any of the functions conferred on an authorised officer under this Part.

(2) An authorised officer appointed under subsection (1) shall be furnished with a warrant of his or her appointment and, when exercising a function conferred on him or her as an authorised officer, shall, if requested by a person affected, produce the warrant, or a copy of it, to that person.

(3) An appointment of a person under this section as an authorised officer shall cease—

(a) where the Authority revokes the appointment,

(b) where the appointment is for a fixed period, on the expiry of that period, or

(c) in the case of a person who, on the date of the appointment, was a member of staff of the Authority, where he or she ceases to be a member of staff of the Authority.