My local Iceland in Holloway Road is selling WKD Blue at £5 for a pack of 10 275ml bottles. That works out at just 50p a bottle. Morrisons just a few hundred yards away is selling a 12 pack for £12.49 so you can see it is a big saving.
I picked up 2 boxes so 20 for £10. Great value.
Do not know if it is nationwide but they were marked reduce to clear and still had plenty of stock when I bought them.