Heads up to anyone trying to avoid Aer Lingus' handling fee by using Entropay.
I found yesterday, after hours of trying to understand why, that basically Entropay Virtual Visa cards, denominated in GBP, are no longer recognised by Aer Lingus as Visa Electron cards.
I tried two Entropay Virtual Visa card numbers (after having created a second card number) to see if the issue was to do with the provisioning of the first card number. Still the same message on the Aer Lingus website "Your card number cannot be processed online. If you are sure your details have been entered in correctly, please contact your card company."
I called Aer Lingus, as I wondered whether their website was playing up. They assured me it wasn't.
I contacted Entropay support, they just said "EntroPay Virtual Cards are categorized, and branded by VISA as the VISA Classic Debit." and told me to select Visa instead of Visa Electron. I replied to Entropay saying that there are many websites and forums that confirm that Entropay Virtual Visa cards that are denominated in GBP are categorised as Visa Electron and not Visa Debit, and that the starting of my card number is 4101 and not 4313. Entropay replied "Please note that it depends on the merchant's payment processor whether it will accept our cards as VISA electron cards. Please note that we have no control over this." Fair enough.
In the end I accepted defeat and transferred more money to my Entropay account, so that I could pay Aer Lingus' €6 per person "handling fee" (and there were 7 of us travelling!). Since I also had to pay Entropay's 4.95% topping up fee, this whole event cost me more than if I had just paid for the flights using my credit card.