Sorry for getting back to this old post but what's the verdict?
Does BA Chase card issued in the US provide CDW in Ireland or not?
Not sure about BA card, but the CSP does cover Ireland and they are both Visa Sig. However you will need to contact Chase in any event as the rental company will demand a letter of proof. Note even then, some will put $5k hold on your card, so make sure you have enough credit line.