Finally ordered a Nvidia GTX 1080 graphics card after waiting until Black Friday/Cyber Monday and being thoroughly disappointed. The only good deal was the £499.99 Gigabyte from ebuyer and I missed it.
Anyways, this is the next best and cheapest Geforce 1080 GPU I could find. Conversion rate including delivery works out to around £530-£550 which is £100 cheaper than anywhere else for this card. It's among the fastest 1080s with a core clock of 1708MHz and boost 1848MHz
Don't hang around: it's currently on order with stock due on December 2nd (this Friday) so I imagine the price will go up again soon or when stock arrives.
Full specifications: http://www.pny.com/geforce-gtx-1080-xlr8-gaming-oc