Where a shop worker gives to his or her employer an objection notice, any agreement entered into between the shop worker and the employer becomes unenforceable to the extent that—
it requires the shop worker to do shop work for additional hours on Sunday after the end of the relevant period, or
it requires the employer to provide the shop worker with shop work for additional hours on Sunday after the end of that period.
A shop worker who has given an objection notice may revoke the notice by giving a further written notice to the employer.
Where—
a shop worker gives to the employer a notice under subsection (3), and
after giving the notice the shop worker expressly agrees with the employer to do shop work for additional hours on Sunday (whether on Sundays generally or on a particular Sunday),
the contract of employment between the shop worker and the employer is to be taken to be varied to the extent necessary to give effect to the terms of the agreement.
The reference in subsection (1) to any agreement—
includes the contract of employment under which the shop worker is employed immediately before giving the objection notice;
includes an agreement of a kind mentioned in subsection (4), or a contract of employment as taken to be varied under that subsection, only if an objection notice is given in relation to the working of additional hours under that agreement or contract as varied.