Where? Extracts from previous link...
31 ... According to the description given, those activities display the characteristics necessary to enable, in principle, those who perform them to be regarded as 'workers' ...
...
33 It follows that the characteristics of the jobs held by the three Turkish nationals ... [satisfy the condition of] being in legal employment.
34 The question nevertheless arises whether, in cases where Turkish nationals ... have au pair or student status, they are thereby precluded from the status of workers ...
35 In that regard, it should first be pointed out that a social objective pursued through granting leave to enter as students or as au pairs, together with the related right to work, does not, of itself, take away the lawful character of the activities performed by the persons concerned and, consequently, does not prevent them from being regarded as 'duly registered as belonging to the labour force' of the host Member State ...
45 Provided that the conditions referred to in paragraphs 27 to 30 of the present judgment are met and provided, in particular, that the genuineness of the work performed by the Turkish nationals in question is confirmed, the fact that they have entered as students in order to pursue a course of studies or as au pairs with the aim of mastering the language of the host Member State is immaterial.
...
Treeesa you need to understand that the way law works is that although these rulings were made in the specific case before the court (which related to the immigration status of Turkish students and an au pair), a subsequent court (of equal or lower precedence) looking at similar circumstances will follow the same arguments.
So whilst in this particular case the UK immigration authority was trying to deny the au pair a particular right which is afforded to workers in the UK on the basis that an au pair has some different status, and the ECJ said that was wrong, if someone goes to an Employment Tribunal (or the Court of Appeal, or the ECJ) and tries to deny an au pair some other right which is afforded to workers in the UK on the basis that they have some different status, the judgement should follow that precedent.
Finally, I am aware of the provisions of the 1969 Council of Europe agreement. Unsurprisingly many of the provisions of this agreement have been superceded. For instance...
'Any contracting party may declare that it reserves the right to consider that the term "person placed au pair" shall apply only to females.'
Try relying on that in court!