The valid issue that Laurence raises is that the very wealthy can effectively choose whether to be a Scottish or UK taxpayers. Guess which one they’ll opt for!
Through my work I know of a couple who have made some perfectly legit modifications to their arrangements to be English taxpayers. So in rough terms, instead of Scotland’s public finances getting 45% of £1m, we get 46% of nothing. It takes an awful lot of peoples’ extra 1% tax to make up for that loss.
Same happens everywhere, like when France hiked its top rates of tax a few years ago, countries like the UK and Belgium benefitted. I sometimes think the world needs a single government and a single tax regime to prevent this sort of thing and all the abuse by large multinationals. But it won’t happen, as nationalists will always insist that each state must be free to do their own thing.