4(1)This paragraph applies to any shop worker who, under his contract of employment—
(a)is or may be required to work on Sunday (whether or not as a result of previously giving an opting-in notice), but
(b)is not employed to work only on Sunday.
(2)A shop worker to whom this paragraph applies may at any time give his employer written notice, signed and dated by the shop worker, to the effect that the shop worker objects to Sunday working.
(3)In this Schedule “opting-out notice” means a notice given under sub-paragraph (2) above by a shop worker to whom this paragraph applies.