isabel,
well there is a strong european and oriental presence in the law faculty (at least in first year, undergrad). European due to the Anglo-French, Anglo-German and European Studies/General Exchange programmes (ERASMUS); oriental due to the sizeable minority of Singaporean and Malaysian students - they were part of the empire after all, and due to good education systems UK universities often recruit large numbers from Singapore and Malaysia.
so my answer is no, there isn't an 'older' feel; international, definitely. but then you will be in london, which is more cosmopolitan than any other city in the world.
sure there are a few mature students, but I doubt King's has any more than any other university.
hope that helps.