A thought experiment, if you will indulge me.
Forgive me, Iain Dale, for asking my readers to imagine your prediction is wrong. Imagine the SNP do better than you've predicted, or UKIP squeeze the Conservatives in a few key marginals. Imagine, in short, that the Conservatives fall a few seats short of an overall majority.
The clear choice of the English people would be a Conservative government, denied by the choices of voters in the rest of the United Kingdom.
I wonder if, in such a position the English would be granted their own Parliament? I won't be holding my breath. The UK can only survive by suppressing England and English cultural identity, in Charles Kennedy's memorable phrase, questioning the very idea of England. It's why the BBC pretend the English don't have a history, or the coursebook for immigrants seeking UK citizenship denies that anyone considers themselves English. It's why you didn't see English on the census form in 2001 and won't in 2011 (but if you're Scottish or Welsh, no such concerns). It's why we get an alphabet soup of regional quangos rather than real democracy.
They won't give the English a parliament because they know once we're given a taste of justice, we will want full independence, and then who will pay for the Scots?