Seems like a good deal. Considering the limited edition content is selling for over £20 on Ebay.
You need to use the walkers code. You need to sign up to walkers and complete a couple of questions then you can get a unique code for a extra 10% off at Zavvi.
If you only use the walkers code, the price will be £43.16.
Dont forget about Quidco or Topcashback.
EDIT : If you wote cold, please explain why. I cant see this game any cheaper new.