I too use two sharp batteries with my 5500, and that works just fine. Rarely, if ever, do I find myself in a jam with this situation and the lesser battery for the 5500 (and I believe the c700) is pretty inexpensive on eBay and at other sellers sometimes. That might be a nice middle road option if you can find one for the right price.
Not sure about the shipping to Europe issue, though. Good luck!