If the European Supply Store had the option of paying in Euros (or GB£), it would eliminate that issue for a lot of customers. But, alas, not me, unless I can somehow pay in Australian dollars!
I still don't really understand what this means. When you are paying money into a European bank account, what valuta are you paying in and how do you know this?
With international transactions you tell your bank a) which currency to use to remove the money from your accounts (usually but not necessarily probably the currency your account is natively using) and b) the currency which should arrive at the target account (again not necessarily the currency the target account is actually using).
If the upcoming BookCrossing EU bank account *receives* money in a currency other than EURo, then the bank will charge a crazy amount for the conversion. Thus we will not be able to accept payments other than in EUR into that account.
If the whole transaction is done in EUR (and happens within the EU / SEPA region) they are not legally allowed to impose additional fees.
This means that British members, who mostly will have their own accounts use GBP, should tell their bank to do the whole transaction in EUR; in other words the conversion needs to take place on their end when the money is deducted from the member's account. That's why I'm interested how UK banks handle such transactions and in how far this results in (high?) fees for the UK bank customers.