Any provision in an agreement is void in so far as it purports -
(a) to prohibit or restrict the making of protected disclosures,
(b) to exclude or limit the operation of any provision of this Act,
(c) to preclude a person from bringing any proceedings under or by virtue of this Act, or
(d) to preclude a person from bringing proceedings for breach of contract in respect of anything done in consequence of the making of a protected disclosure.