17(1)Any provision in an agreement (whether a contract of employment or not) shall be void in so far as it purports—
(a)to exclude or limit the operation of any provision of this Schedule, or
(b)to preclude any person from presenting a complaint to an industrial tribunal by virtue of any provision of this Schedule.
(2)Sub-paragraph (1) above does not apply to an agreement to refrain from presenting or continuing with a complaint where—
(a)a conciliation officer has taken action under section 133(2) or (3) of the 1978 Act (general provisions as to conciliation) or under section 134(1), (2) or (3) (conciliation in case of unfair dismissal) of that Act, or
(b)the conditions regulating compromise agreements under the 1978 Act (as set out in section 140(3) of that Act) are satisfied in relation to the agreement.