What makes you Scottish?

Now that the deal is done, some aspects of the forthcoming referendum on Scottish independence remain puzzling. I suspect that Mister Salmond thinks he has won a major concession by including young people under 18 in the vote; he’s a pragmatic operator and will no doubt fancy his chances of persuading younger voters of the benefits of independence. Lowering the voting age is quite an innovation for a party which, not so long ago, raised –from 16 to 18- the age that cigarettes could legally be bought and would like to raise the legal age for buying alcohol from 18 to 21. The Scottish government appears not to see (or chooses to disregard) any contradiction between granting these young folk a say in the most important political issue of the last 300 years, but not allowing them to have a fag while they think about how to cast their vote. And, at the very least, it seems something of an oddity that a kid of 16 or 17 will be able to vote in the referendum but not in a general election. I've yet to hear a convincing explanation as to how that makes sense.

Another troubling aspect of this referendum is that any British, Commonwealth or EU citizen will get to vote, as long as they are resident in Scotland. A Frenchman working in the oil industry and living in Aberdeen, for example, will get the chance to determine Scotland’s future, but a Scotswoman who has moved as far south as Durham will have no say.

I know that if I moved to Manchester tomorrow, I wouldn’t presume to describe myself as a Mancunian and wouldn’t expect to have much of a considered opinion on issues pertaining to political life in Manchester; my roots would remain in Scotland and I’d still consider myself Scottish. According to estimates, there are around 800,000 Scots living in England, Wales and Northern Ireland. It would not be unreasonable to guess that a high proportion of these exiles might think like me and would wish to have a stake in the future of their country but, in the 2014 referendum, they will be disenfranchised. What exactly would be difficult about arranging a postal vote for these exiled Scots? Perhaps the main ‘difficulty’ is that Mr Salmond has calculated that people who have moved south for economic reasons might be more inclined to vote in favour of the union.

One of the big arguments being put forward is that the independence issue shouldn't hinge on our ethnicity. The ‘Scotland’ that will vote is merely the diverse community of peoples who happen to be registered to vote here in 2014. I have no particular difficulty with the argument that the cultural or ethnic background of the voters isn’t that important, but surely you can’t have it both ways?
If 'Scottishness' is not about your ethnicity, but is mainly about your post code, what exactly is the point in going to all this fuss to break up a partnership that has worked for more than 300 years? If someone can move a few miles up the road from Carlisle to Langholm and instantly become ‘Scottish’, what’s the big deal about national identity?

What exactly is the point of 'Scottishness' if there is no ethnic component to it? And if there is an ethnic component, why are we denying 800,000 Scots the right to vote?