Today, the European Council has published a document of guidelines with a view to the opening of negotiations on the overall understanding of the framework for the future relationship EU-UK. In our field of interest those are the relevant ones
10. The future partnership should include ambitious provisions on movement of natural persons, based on full reciprocity and non-discrimination among Member States, and related areas such as coordination of social security and recognition of professional qualifications. In this context, options for judicial cooperation in matrimonial, parental responsibility and other related matters could be explored, taking into account that the UK will be a third country outside Schengen and that such cooperation would require strong safeguards to ensure full respect of fundamental rights.
Judicial cooperation in civil matters is not mentioned.
Guidelines 7 and 15 refer to the CJEU:
7. The European Council further reiterates that the Union will preserve its autonomy as regards its decision-making, which excludes participation of the United Kingdom as a third-country in the Union Institutions and participation in the decision-making of the Union bodies, offices and agencies. The role of the Court of Justice of the European Union will also be fully respected.
15. Designing the overall governance of the future relationship will require to take into account:
iii) the requirements of the autonomy of the EU legal order, including the role of the Court of Justice of the European Union, notably as developed in the jurisprudence.