Will they not let you pay in sterling? I always use the .com of websites be it car hire or purchasing goods instead of the .ie. You get a much better exchange rate on your credit card than they give on the purchase exchange rate. For example I saved ?185 recently on car hire for the same car with the same company by paying in Sterling on their .com website!!
Nope, they wont, when you go through the checkout (and prices are in sterling) it says theres a problem with your order re: delivery address, it makes you change to Euro's