I noticed this at my local sainsburys, it had a promotional barker so I would assume its nationwide.
Was looking to get my wife the normal box of premium chocs and noticed this was half the price and even bigger, quite the bargain. This one is 473g compared to the online ones at 430g and 485g, priced 12.25 and 14.99 respectively
The pic is not exactly accurate, could not find the exact one, it's got xmas baubles on it, its a huge box though so hard to miss
Sorry if its already been posted but this was instore only it would seem (my local sainsburys is in wigston leicster if anyones after specifics)