Section 20. Vacancies, etc., not to invalidate proceedings of Board

20. Vacancies, etc., not to invalidate proceedings of Board.— No act or proceeding of the Board shall be invalid merely by reason of— - (a) any vacancy in, or any defect in the constitution of, the Board; or (b) any defect in the appointment of a person acting as a Member of the Board; or - (c) any irregularity in the procedure of the Board not affecting the merits of the case.