I noticed these just before Christmas at this price and thought I'd have to wait a week or two. I went into the store today to be greated by a new price label of £322. I was informed that the price went up 2 days ago and there wasn't anything they could do. Something to do with the exchange rate.
I then got chatting to another sales assistant who mentioned that they were still scanning at the lower price of £292.63. This is atleast £30 cheaper than anywhere else I've seen, and I was able to walk away with one.
It seems that Carphone Warehouse only do the NC10 at the Westfield London store, but if you're in the area (and their computer hasn't been updated) you might get lucky.