The best way for the Koreas to trade would to set up an enterprise zone somewhere near the DMZ. Unfortunatly, as you noted, North Korea is hardly a bastion of stability and entrepreunerial spirirt! However, the North has adopted the euro as it's main currency, having ditched the dollar back in 2002, so there wouldn't be a huge currency problem.
As for LSE, no I won't be taking a gap year, as I'm still in year 12. Is that what you're planning on doing? It's not so much about hard work to be honest, because I'm pretty sure I can get the grades needed for Economics, but even with 5 A's people are rejected year after year.