Where to buy a gaming laptop (UK)

[Euphonium]

I'm looking to buy a new gaming laptop in the UK, with a budget of ~£800
Has anyone had good or bad experience of any of the following companies, or could recommend another supplier I should consider?

[urlExt=http/3xs.scan.co.uk/custom/custompcs/laptop]Scan[/urlExt]
[urlExt=http/www.novatech.co.uk]Novatech[/urlExt]
[urlExt=http/www.pcspecialist.co.uk/laptop-computers/]PCspecialist[/urlExt]
[urlExt=http/www.chillblast.com/Laptops]Chillblast[/urlExt]
[urlExt=https/www.cyberpowersystem.co.uk]CyberPower[/urlExt]

A rough wishlist would be:

15" 1080p screen
Windows 7
mid-range switchable graphics.

I'd also be interested in a system with no drives or OS, as I could carry them forward from my old PC and use the money saved towards better CPU & GFX

Thanks in advance

 

[iceclock]

http/www.scan.co.uk/products/156-gigabyte-p15f-core-i7-4710mq-8gb-1tb-nvidia-geforce-gtx-850m-2gb-win-81

 

[Euphonium]

Looks nice, but is the i7 worth it over an i5? Also, a pre-built won't let me re-use my existing drives or OS

 

[iceclock]

ur limited budget will limit you sir