With regard to a Member State in which two or more systems of law or sets of rules concerning matters governed by this Regulation apply in different territorial units:

1. (a)

   any reference to habitual residence in that Member State shall refer to habitual residence in a territorial unit;

2. (b)

   any reference to nationality, or in the case of the United Kingdom ‘domicile’, shall refer to the territorial unit designated by the law of that State;

3. (c)

   any reference to the authority of a Member State shall refer to the authority of a territorial unit within that State which is concerned;

4. (d)

   any reference to the rules of the requested Member State shall refer to the rules of the territorial unit in which jurisdiction, recognition or enforcement is invoked.