4. (1) A provision in any agreement shall be void in so far as it purports to exclude or limit the application of any provision of this Act or is inconsistent with any provision of this Act.

(2) A provision in any agreement which is or becomes less favourable in relation to an employee than a similar or corresponding entitlement conferred on the employee by this Act shall be deemed to be so modified as to be not less favourable.

(3) Nothing in this Act shall be construed as prohibiting the inclusion in an agreement of a provision more favourable to an employee than any provision in Part 2.

(4) References in this section to an agreement are to any agreement, whether a contract of employment or not and whether made before or after the commencement of this Act.