Athena Capital Fund Sicav-Fis SCA & Ors v Secretariat of State for the Holy See  EWHC 3166 (Comm) features as defendant the Secretariat of State of the Holy See (not the Holy See itself), and relates to a fraud and embezzlement claim of property in Chelsea, London.
Defendant says that from the perspective of Claimants, the purpose and intention of bringing these proceedings is to try to influence the criminal process in Italy, and/or the publicity emanating from the criminal process.
For its jurisdictional challenge, defendant argues  i) The claim was not a “civil and commercial matter” within the meaning of A1(1) BIa; ii) one of the claimants was not a party to the relevant Sale and Purchase Agreement (SPA) and could not rely upon it [this was summarily dealt with  by suggesting an amendment of claim] and, more forcefully, (iii) Defendant was not a party to the SPA for the purposes of A25 BIa.
Salzedo J justifiably in my view held  that
whether the claim is a civil or commercial matter does not turn on the subjective intentions of the claimant as to the ultimate effect that a claim might have on its interests, but on an objective reading of the claim itself and the relief that it seeks from the court. On that basis, it is a claim for declarations against the Defendant concerning the Defendant’s entry into commercial transactions with the Claimants.
and that the transaction was not entered into by the Defendant in the purported exercise of public powers: 
The Transaction was one that any private person could have entered into if it had the requisite funds. Nothing that was essential to the Transaction required sovereign powers to enter it and nothing that the Defendant did or purported to do was in the exercise of public authority.
As for the defendant not being a party to the SPA, the context here is whether a party involved in the signing accepted the SPA and its choice of court as an agent of the defendant. The judge, confirming the parties’ consensus, points out that that agency issue befalls to be addressed by English law. It is not said why that is the case however it is of course the result of the amended A25 – as others before it, however, the court does not complete the lex fori prorogati analysis with the recital 20 in fine mandated renvoi. On the agency issue the judge holds there is a good arguable case that the relevant agent did bind the defendant.
Next  ff follows a CPR-heavy discussion on the amendment of the claim form, seeing as the claimants erroneously assumed  that BIa was not engaged as the Vatican is not party to Brussels Ia. At  the conclusion is that the claim form may be amended and that defendants’ time spent in dealing with the service out issues under the common law (a wasted exercise as BIa applied), may be met in the costs order.
Once the A25 point rejected, there would have been a most narrow window for any kind of stay, yet the defendants try anyways, with  a series of abuse and case management arguments. One particularly poignant one is that the proceedings would interfere with a criminal proceeding. After discussion the judge  dismisses the idea on the facts, seeing as none of the declarations sought would involve any assertion as to what does or does not amount to criminality as a matter of the law of the Vatican State.
 ff discusses the abuse of process issue which the defendants, I understand, presented more or less as being integrated into the criminal procedure element, discussed above. That was wise, for abuse of process, while entertained among others in Vedanta, is arguably noli sequitur in a BIa claim. [Support for the alternative view here was sought [172ff] in Messier-Dowty v Sabena SA 1 WLR 2040]
The case-management stay proper is discussed 192 ff with reference ia to Municipio, and Mad Atelier. The judge in current case is very aware of not re-introducing through the back door what CJEU Owusu shut the front door on. He summarily discussed the possibility anyway, only to reject it.
An interesting case.