Quick history lesson. The formal title of the UK is the United Kingdom Of Great Brittan, which is comprised of the countries England, Scotland, Wales and Ireland governed by the English parliament in Westminster, London. After the Romans pulled out the British islands formed many small kingdoms which slowly merged into the countries as listed then the English kings waged several wars to bring the other countries under English rule. ever since the populations of these regions have campaigned with differing tactics, both political and militarily for independence. The most recent of the violent uprisings are the "Troubles" in Ireland which as it stands are currently non violent with the formation of the Republic of Ireland and devolved power to Northern Ireland in the form of the Norther Irish Assembly. Wales and Scotland have been able to negotiate their own assemblies but these are still answerable to Westminster in matters of the treasury and certain aspects of law making. Now some sections of all three countries want full independence, Ireland and Scotland being the most vocal, though Ireland is currently focusing more on establishing a stable political system at the moment. Wales is working more behind the scenes and I dont think there is a huge movement to see it happen. What is interesting about the Scottish elections is that the SNP (Scottish National Party) who's main focus is supposed to be on independence won the majority while making little mention of independence during the campaign but are calling the win a mandate for independence which is proving a little controversial both sides of the border.
Speaking as a native scot, most people aren't batting an eye at the SNP's mention that they intend for a referendum on independence. It has always been a MAJOR part of their manifesto, it was mentioned gods know how many times in the run up to the election, and it's not a huge issue. Most people I talk to welcome the idea (And this is a broad spectrum, as I work in a petrol station and chat to most of my customers), because it won't be an immediate thing, and with an SNP majority and a few years until the proposed referendum, we will manage to see how the nation fairs at their helm, and WE will decide when the vote comes. If we think that they prove that Scotland has a brighter future without England, we will decide that at the poll.
And, the Union of Crowns is ONLY 300 years old. Scotland/Pictland/Caledonia was an independent nation a hell of a lot longer than that, even resisting the roman empire (or rather, the Roman Empire gave up trying to tame the worthless barbarians after they lost a Legion or two, as even their victory at Mons Graupius couldn't bring them to heel). So, your history lesson is riddled with innacuracy.
However, your comment on how the SNP's election is being percieved down in England (including an innacurate statement about how we're recieving it) seems to be characteristic of what my English friends are being told (Those who live in England, I mean), so clearly the disinformation/rumour mill is hard at work. (One particularly amusing one pointed out that Alex Salmond is being made out as a rabid secessionist who would use military means if possible, which, if true, could not be farther from the truth).
Another comment about their election campaign, Independence was mentioned, but so was the things that they had achieved and the things they were still attempting to. Labour sunk their campaign by making it very negative, and by having a history of voting contrary-wise to the SNP, out of spite (As voiced by one of Labour's own MPs, who came forward on the election morning in disgust, citing an incident he experienced). Lib Dems, well, no brainer there. Tories, they held the majority of their seats, small as that is.