.... once we are gone the rest of the Union will be stuck with a Tory government for evermore (see above map), and it is unlikely that they would want the Scots back on board as we are not known for our Tory voting tendencies (see same map above!).
I'm not so sure. Those maps look overwhelmingly blue because of large rural constituencies, but small urban ones are much more likely to be Labour. We aren't governed by the party which holds the biggest area !!

Furthermore, Labour will have to re-invent itself if it loses the 50-odd seats in Scotland. It will have to move further towards the centre ground of (remainder)UK politics. Either that, or lose out to the Lib Dems in the long term.
It is an interesting fact that the only election since 1979 which would have produced a different result if the Scottish vote were excluded was the last one, 2010, which would have returned a Conservative majority rather than a hung parliament.
Scotland going would certainly give rUK a better chance of having a government which reflects the will of England. Our politics has been heavily skewed by Scotland, particularly during the Blair/ Brown era, and this may well be part of the reason why Scottish independence is more popular in England than in Scotland. That, and the constant whining from the ultra-nationalists in Scotland.
Mike