Found this in GAME at the Junction 32 outlet in Castleford yesterday.
Seems to be sold out on-line, but they definitely had more stock in store.
Note: If you are after just the zombie dlc code, as I was, trade in price was £34.
First deal I've posted, so please be gentle!!
Edit: Forgot to mention that I got NUS too, so it actually only cost me £49.50.