Yes, buying books in Europe is becoming very awkward, what with the formats and the location issues. Just changing your location does work on occasions & on other, some sites decide your credit card address is your location.
By the way,
www.iliadreader.co.uk sell ebooks (mobi only) and do have prices cheaper than some other sites on occasion, but you do have to know what you want as their website isn't the easiest to find a book...