"If they only stand in Scotland and Wales, they should not influence UK matters. I'd love to see both of them given independence, and see how long they'd last."

Scotland and Wales are full integral parts of the UK so of course they have every right to stand in UK elections and influence UK matters. I'm not sure that any of the major parties actually stand througout the entire UK! There are of course different opinions as to whether Scotland would be better or worse off outwith the UK but the idea that it would be incapable of doing so is absurd.

As for the independence question itself. A majority of Scots tend to still favour the union in some form (from the status quo,to more devolved powers, to full fiscal automony within the UK) though there is also a substantial number who favour outright independence. The question has never been fully debated or put to the Scottish people. The SNP manifesto at the last election was to organise an independence referendum and poll after poll has shown that a clear majority of people living in Scotland favour a referendum - but they can't get it through the parliament because they need the support of at least one of the major unionist parties all of whom are opposing any referendum. Hence the Scottish government can't get through one of its main manifesto aims. The wheels haven't come off the bus though and the administration has gone along with other aims hoping they can at sometime persuade perhaps the Lib Dems to give support. People just have to get used to the idea that with no overall majority governemnts can't just do everything they want.