reg 31 Warrant officers and OR-7s
(1) For any proceedings with lay members where every person to whom the proceedings relate is of or below the rank or rate of warrant officer, the number prescribed for the purposes of section 155(3) (that is to say, the number of lay members who may be warrant officers or OR-7 ranks rather than officers) is — (a) one, if there are three or four lay members; or (b) two, if there are five or six lay members. (1A) The number prescribed by paragraph (1) may consist of, or include no more than, one OR-7 rank if every person to whom the proceedings relate is of or below that rank or rate. (2) For any proceedings with lay members where any person to whom the proceedings relate is an officer subject to service law, every lay member must be an officer qualified for membership under section 156 and not ineligible by virtue of section 157 or rule 32; and section 155(3) shall not apply in relation to any such proceedings.