Notwithstanding anything contained in the Industrial Disputes Act, 1947 (14 of 1947),the provisions of each of the settlements, in so far as they relate to the payment of an annual cash bonus to every Class III and Class IV employee of the Corporation at the rate of fifteen per cent. of his annual salary, shall not have any force or effect and shall not be deemed to have had any force or effect on and from the 1st day of April, 1975.