http://www.legislation.gov.uk/eur/2016/1104/article/24Council Regulation (EU) 2016/1104 of 24 June 2016 implementing enhanced cooperation in the area of jurisdiction, applicable law and the recognition and enforcement of decisions in matters of the property consequences of registered partnershipsCouncil Regulation (EU) 2016/1104Council Regulation (EU) 2016/1104 of 24 June 2016 implementing enhanced cooperation in the area of jurisdiction, applicable law and the recognition and enforcement of decisions in matters of the property consequences of registered partnerships2020-12-11King's Printer of Acts of Parliamenthttps://webarchive.nationalarchives.gov.uk/eu-exit/https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:02016R1104-20160708texttext/xmlen2016-07-08CHAPTER IIIAPPLICABLE LAW
Article 24Consent and material validity1.

The existence and validity of an agreement on choice of law, or of any term thereof, shall be determined by the law which would govern it pursuant to Article 22 if the agreement or term were valid.

2.

Nevertheless, a partner may, in order to establish that he did not consent, rely upon the law of the country in which he has his habitual residence at the time the court is seised if it appears from the circumstances that it would not be reasonable to determine the effect of his conduct in accordance with the law specified in paragraph 1.