I wonder if it has something to do with the fact that it's discounted.
Buy new: £299.99 £279.99
You save: £20.00 (7%)
The Amazon bestsellers list is a nice way to find discounted items. That's how I found Wii Play for 25 € at amazon.de. I immediately ordered it, and, unsurprisingly, after a few hours it was sold out.
My Mario Kart Wii friend code: 2707-1866-0957