Did you try telling it you were in the UK? At the bottom of the page there is a line that says "Choose region:" then has 5 little flags and a world map - presumably if you click the British flag you can get the UK version. (I didn't see any prices on that page, but I did notice an actual US tool-free phone number there. Clicking the British flag does show me a different phone number.)
As far as why you saw the US page ... do you use Turbo? Turbo uses a proxy, which can result in websites thinking you are somewhere other than your actual location. While I have to doubt they'd route you through a proxy over here, maybe they show the US site for people they think are in Norway. Or else, maybe the "world" site uses US dollars?