Purchasing showkase in UK

It is not possible to change the currency during purchase (to actually pay in GBP) but you can still use a UK debit or credit card to buy Showkase. Your card issuer will convert the amount to GBP for you (please check with them for their current rates) and they may, or may not, charge a non-sterling transaction fee (again, please check with them to be sure). Some may charge a flat fee of around £1.50, others may charge a percentage of the transaction and others may not charge at all. It really depends on your card issuer and their own terms and conditions.