18.—(1) The nominated officer shall be selected by the deputy chief constable.
(2) The nominated officer shall be–
(a)a constable of the police force concerned or, if the chief constable of another police force is requested by the deputy chief constable and agrees to provide a nominated officer, a constable of that other police force; and
(b)a constable of a rank which the deputy chief constable considers to be appropriate.
(3) The nominated officer shall not be–
(a)a chief constable;
(b)a deputy chief constable;
(c)any constable who the deputy chief constable considers is or appears to be a material witness to the complaint, report or allegation which has been received; and
(d)any other constable who the deputy chief constable considers is or appears to be an interested party.