21.—(1) For the purposes of Part V of the 1986 Act, a woman's normal weekly earnings shall be calculated in accordance with the following provisions of this regulation.
(2) In this regulation—
“the appropriate date” means
“normal pay day” means
“day of payment” means
(3) Subject to paragraph (4), the relevant period for the purposes of section 50(3) of the 1986 Act is the period between—
(a)the last normal pay day to fall before the appropriate date; and
(b)the last normal pay day to fall at least 8 weeks earlier than the normal pay day mentioned in sub-paragraph (a),
including the normal pay day mentioned in sub-paragraph (a) but excluding that first mentioned in sub-paragraph (b).
(4) In a case where a woman has no identifiable normal pay day, paragraph (3) shall have effect as if the words “day of payment” were substituted for the words “normal pay day” in each place where they occur.
(5) In a case where a woman has normal pay days at intervals of or approximating to one or more calendar months (including intervals of or approximating to a year) her normal weekly earnings shall be calculated by dividing her earnings in the relevant period by the number of calendar months in that period (or, if it is not a whole number, the nearest whole number), multiplying the result by 12 and dividing by 52.
(6) In a case to which paragraph (5) does not apply and the relevant period is not an exact number of weeks, the woman's normal weekly earnings shall be calculated by dividing her earnings in the relevant period by the number of days in the relevant period and multiplying the result by 7.