Italy got unified in 1861 only under a political point of view, the true unification of the population started 60 years ago(shortly after the war) and is still finding many obstacles. There's no such thing in the UK or in America.
Actually, it's
extremely similar to the unification of the UK, we've been politically unified for years, but we've never really been unified, we've always been four very distinct cultures, English, Irish, Scottish and Welsh, no legal document has ever changed that.
I agree that most of the better educated people, from most countries would probably be aware of who Churchill is, but I don't think it is those who were asked to be honest.
Let me give you an example of how these statistics work:
I could go out into the streets of Rome and ask people whether they thought the UK should lift it's trade embargo on food being exported to Ethiopia so that some of the starving population could be fed, and I assure you that I would get a fair number of 'Yes' answers, despite the fact that
no such embargo exists, there is, in fact, only an arms embargo.
Now, if I were of a sensationalist turn of mind, I could read that as 'X% of Rome's citizens are ignorant to world events', if I were in a benevolent mood, I could describe it as 'X% of Rome's citizens are in favour of helping Ethiopia', if I were in a Vindictive mood I could say 'X% of Rome's citizens assume the worst of the UK'. It's all down to interpretation.
Edit: Edited, wasn't happy with possible misinterpretation of part of the post.