That is not a true representation of the EU declarations of existing, controlling laws or its position on retroactive application of EU law after 29 March 2014. (1) UK persons are still members of EU jurisdiction, today and until 29 March 2019. (2) UK withdrawal does not per se extinguish private party contractual obligations.

"Judicial Cooperation in Civil and Commerical Matters" (pdf, 13 July 2017)

I. General principles The following principles should apply in accordance with Union law, as interpreted by the Court of Justice of the European Union on the date of entry into force of the Withdrawal Agreement:

(1) The relevant provisions of Union law applicable on the withdrawal date on the applicable law for contractual and non-contractual obligations should continue to apply to contracts concluded before the withdrawal date, and (regarding non-contractual liability) to events which occurred before the withdrawal date. ...

&tc.

EU will enforce those claims.

The UK gov't however is unlikely to intervene in EU or EU27 venue litigation between private parties unless invited by same. (1) It's too cheap to spend. For this reason, UK.gov has invested in a PR campaign --which I'v surmise has alarmed you-- to persuade the world to select UK jurisdiction for all its legal needs, because "continuity".

Diversity is the key to economic and political evolution.