Not sure if this has been mentioned but a work colleague told me this little titbit. I checked and it's true.

Whilst most credit card companies charge a 'transaction fee' on foreign purchases (2-3% normally) the Nationwide Credit Card does not.
I have also been reliably informed by the same person that the exchange rate is normally a little better than M&S rates, who are normally the best place for exchange rate on the High Street to get your currency.

My application is in the post

Brizzle.