Amazon are now selling the White (8gb) Wii U for 149, like ASDA. Linky. But Amazon also have a 'game for 20 pounds when you buy a Wii U' deal. Looks a good deal..
That's a good deal! You don't care about the lack of storage on the Wii Basic, 'cause you can use just an external HDD with the system via the USB ports. I am not sure though (I just thought of that) how performance is effected, as USB is uni-directional at a time, and potentially slower than the SSD in the system. But not one raised concerned, so I think it's fine.