(1) In determining whether employees are employed in an undertaking that meets a relevant workforce threshold, the number of employees in the undertaking shall be reckoned by calculating the average number of employees employed in the undertaking during the 2 years before the date that a request is -

(a) made under subsection (2),

(b) received under subsection (4) by the Court or a nominee of the Court, or

(c) received under section 7 by the employer, the Court or a nominee of the Court.

(2) Without prejudice to subsection (4), following a request from one or more employees or employees' representatives (or both), the employer shall provide details of the number of employees in the undertaking during the period referred to in subsection (1) to those employees or employees' representatives (or both) not later than 4 weeks from the date of receipt of that request (but that period of 4 weeks may be extended by agreement between the parties).