re: 10 more countries
That's why it's important to have a European Constitution.
The Euro has everything to do with a single market. We all need to earn a living, eat, sleep, cure, move, travel, consume things and if everybody has the same mean of exchange (same currency), then it's all according to the real value of things rather than artificially elevated or reduced currencies.
Besides, the Brits are completely unable to find any wrongdoings with the Euro. It is managed with great care by the ECB.
Raoul