Thank you Angharad Parry for flagging  EWCA Civ 1609 Koza v Akcil – Angharad has excellent factual background. The case concerns the application of Article 24(2) of the Brussels I Recast Regulation, which assigns exclusive jurisdiction to the Courts of the Member State of the seat in matters relating to the life and death of companies and of the validity of decisions made by their organs:
in proceedings which have as their object the validity of the constitution, the nullity or the dissolution of companies or other legal persons or associations of natural or legal persons, or of the validity of the decisions of their organs, the courts of the Member State in which the company, legal person or association has its seat. In order to determine that seat, the court shall apply its rules of private international law;
Referring particularly to C-144/10 BVG and to C-372/07 Hassett, the Court of Appeal at 28 correctly suggests Article 24’s exclusive jurisdictional rules need to be interpreted with their limited purpose in mind: ‘when article 24(2) speaks of proceedings having an “object” it is not referring to the purpose of the proceedings. Rather that phrase is to be interpreted as “proceedings which are principally concerned with” one of the types of subject matter within the article.’ At 37: ‘The task for the court in each case is therefore to determine whether the proceedings relate principally to the validity of the decisions of an organ of the company. A mere link to a decision of the company, or an issue raised which is ancillary to the heart of a contractual or some other dispute, is insufficient to bring the proceedings within the exclusive jurisdiction.’
Floyd LJ at 46 summarises the direction for courts: ‘I do not take from the English or European authorities which were cited to us any suggestion that one is required in all cases to disentangle issues which are interlinked in this way and apply Article 24(2) to each issue separately. On the contrary, faced with such proceedings, the court is required to form an overall evaluative judgment as to what the proceedings are principally concerned with. The position is obviously different from a case where two quite independent claims are made in the same proceedings. Exclusive jurisdiction in relation to each claim would, in those circumstances, have to be determined separately.’ In the case at hand the case was found overall and fundamentally to concern one and the same issue of the validity of decisions of the organs of the company
Consequently the issue is one of looking beyond the particulars of form and into the true nature of the proceedings. Not a decision always made with ease.
(Handbook of) EU Private International Law, 2nd ed. 2016, Chapter 2, Heading