(1) Whenever an arbitration tribunal consists of more than one arbitrator and any vacancy occurs in their number the tribunal may, with the consent of the parties, act despite such vacancy.
(2) Whenever the tribunal consists of an arbitrator, assisted by assessors and any vacancy occurs in the number of assessors the tribunal may in the discretion of the arbitrator either act despite such vacancy or consent to another assessor being nominated and appointed to fill such vacancy.
(3) An act, proceeding, or determination of the tribunal shall not be called in question or invalidated by reason of any such vacancy, provided that in the circumstances referred to in subsection (1) hereof the required consent has been first obtained.