£700-£800 First Gaming PC

What will you be doing with this PC? Be as specific as possible, and include specific games or programs you will be using.

Mostly playing games on it like GTAV, LoL, Fallout 4 and The Witcher 3

What is your maximum budget before rebates/shipping/taxes?

My max budget would be £800

When do you plan on building/buying the PC? Note: beyond a week or two from today means any build you receive will be out of date when you want to buy.

By Christmas time

What, exactly, do you need included in the budget? (Tower/OS/monitor/keyboard/mouse/etc)

I need a case, an OS (prefer win 7 or 8) and a keyboard if you can squeeze one in

Which country (and state/province) will you be purchasing the parts in? If you're in US, do you have access to a Microcenter location?

UK, Scotland to be exact

If reusing any parts (including monitor(s)/keyboard/mouse/etc), what parts will you be reusing? Brands and models are appreciated.

Only peripherals I have are a Razer Naga 2014 and a Soundblaster wireless headset

Will you be overclocking? If yes, are you interested in overclocking right away, or down the line? CPU and/or GPU?

I may be interested in overclocking down the line, just the CPU

Are there any specific features or items you want/need in the build? (ex: SSD, large amount of storage or a RAID setup, CUDA or OpenCL support, etc)

Would appreciate a 250GB SSD

Do you have any specific case preferences (Size like ITX/microATX/mid-tower/full-tower, styles, colors, window or not, LED lighting, etc), or a particular color theme preference for the components?

Don't need anything fancy, so long as it works!

Do you need a copy of Windows included in the budget? If you do need one included, do you have a preference?

Yes, I prefer win 8 but win 7 is fine as well

Extra info or particulars:

I don't have a monitor at the moment but I just want to put the whole budget into the PC and save up for the other peripherals I need down the line.