12. A casual vacancy in the Bar Council shall be filled,- (a) if the person who previously filled that vacancy was a member, by the person who received the highest number of votes next after that member, in the same election, and in the event there being no such person, by co-option by the Bar Council of a person eligible for election to the Council under this Order; and (b) if it occurs in the office of the ¹[* * *] Vice-Chairman, by a person elected in the prescribed manner by the members of the Council from amongst themselves.