6. (1) The meetings of the Board shall be held at such time and places and in such manner as may be prescribed: Provided that, until so prescribed, such meetings shall be held at such times and places and in such manner as may be determined by the Chairman. (2) To constitute a quorum at a meeting of the Board, not less than three members shall be present. (3) All meetings of the Board shall be presided over by the Chairman or, in his absence, by a member authorised in writing by the Chairman. (4) At a meeting of the Board, each member shall have one vote and, in the event of equality of votes, the member presiding shall have a second or casting vote. (5) No act or proceeding of the Board shall be invalid or be called in question merely on the ground of existence of any vacancy in, or defect in the constitution of, the Board.