Are a provision in a collective agreement and an employer’s practice, pursuant to which, for the purposes of remuneration and promotion, the length of service of a part-time female employee whose working hours are ‘distributed vertically’ over the whole year is to be calculated solely on the basis of time actually worked, contrary to Clause 4(1) and (2) of the Framework Agreement on part-time work [annexed to] Council Directive 97/81/EC of 15 December 1997, and to Articles 2(1)(b) and 14(1) of Directive 2006/54/EC of the European Parliament and of the Council of 5 July 2006 on the implementation of the principle of equal opportunities and equal treatment of men and women in matters of employment and occupation (recast)?