Scotland, Northern Ireland and Wales are all more pro-EU than England, that's one factor (though not the biggest) in the Scots' abhorrence of the Conservatives. I suspect that Cameron and Osborne might be a little less eager to promise the Europe referendum if it was held in England alone, where the Eurosceptics' chances are a good bit better - they're both smart enough to realize that while their Eurosceptics are an immensely useful tool to give Britain more power to reject EU decisions it doesn't like, actually leaving is a terrible idea.

I don't think the Scots are that radically leftist - first past the post always exaggerates such differences. But they are left of centre, definitely. The whole thing reminds me quite strongly of Québec actually - which has also shown that such things can turn around quite rapidly in some circumstances, provided of course that the separatists aren't needlessly alienated even further. Cameron played some dangerous games in that regard in the election - he'll try to undo the damage now of course, but not sure how successful he'll be.

I do agree it will have to change, and the same may be true for the euro, but dropping it entirely seems unlikely. The thing with the anti-EU parties is that essentially all of them are populist parties (whether left, right or far-right on some points and left on others) who fail to offer answers that are at all realistic. If one of them ever came to power, the country in question would be doubly screwed - once for leaving the EU and once for having been idiotic enough to vote a populist party into power without the slightest clue of what they would actually do when faced with the reality of government (a bit like Syriza in Greece, except that Greece would almost literally collapse if leaving the EU right now, so they have no choice but to stay in, at almost any price). The Eurosceptics in the Conservative party are a little better, but the party leadership knows well enough that actually leaving would be a bad deal for Britain - it's only threatening to leave that is useful.