dasulman :
pcspecialist.co.uk - look at the cosmos 15 - you get the gtx 850M for free and can get an I7 config for around £700 with 8GB ram easily that'll do the job.
Specs on the one I linked:
Intel® Core™ i7-4700MQ Haswell Quad Core Processor
15.6" HD Matte Screen
Microsoft Windows 8.1 64bit
16GB DDR3 RAM
1000GB 7200 RPM HDD
DVD Rewriter
Dedicated GT 750M 2GB Graphics
USB3 | HDMI | Bluetooth
2 Year Cube Warranty
Brushed Mineral Grey