I bet many of you never thought I'd say that!
But no, it's not that single currency that's at issue. Instead David Mundell is bringing a Private Member's Bill that would require the acceptance of Scottish banknotes on the same basis as Bank of England ones. (BBC News: 'Legal' bid over Scots banknotes)
I have to say I've never had much of a problem with Scottish notes myself, but normally when I do come back from Scotland I aim to spend the notes in London where they're relatively well known, or even break them all in Scotland so I don't have any. However I gather they are more problematic in the country.
Where I have had problems though are with Northern Irish banknotes, even in places that don't give Scottish notes a second glance. This is probably because they're much rarer down here. I hope that when the Bill is finally presented it will place them on the same footing as Scottish notes throughout the UK. Being able to shop and order with confidence that the money in your pocket will be accepted wherever you are in the UK is straightforward common sense and I'm surprised it's taken this long to enact.