This is the cheapest i've seen so far.
They also have it on the Wii for £56.99, Xbox 360 for £59.99 & the PS2 for £44.99.
Plus all the prices include free delivery.
Don't forget that there is also 5% on Quidco.
I've only seen this online so i'm not sure if its available in store at the same price or not.
I hope this is useful.