Okay, now that i'm at a computer I can respond to you properly. A k-series cpu is off the books, I can spend up to £200 on a cpu, however I would probably go second hand. The reason for this is that my mobo is not overclocking. I built this thing 3 years ago and I don't have the budget for a new mobo, cpu and copy of windows, at that point I may just build a new pc.
This was my original build, not made to turn heads but to be a great bang for my buck pc.
CPU: Intel i5 4460 Quad Core £147.99
GPU: MSI GTX 970 £268.98
Case: Cool Master N200 Micro ATX case £37.23
Motherboard: Gigabyte H97M-HD3 micro ATX Motherboard £69.34
Hard Drive: Seagate ST2000DX001 2TB Desktop 3.5 inch SSHD Internal Solid State Hybrid Drive £72.98 - Amazon
RAM: Ripjawsx ddr3 1600mhz 16GB £63.91
PSU: XFX TS Series 650 W Full Wired Power Supply Unit £68.99
DVD/CD Drive: LiteOn IHAS124-14 24x SATA Internal DVDRW - Black £13.80
Windows: Windows 10 32 bit and 64 bit DVD £79.17
Monitor: Asus moniter HDMI,VGA,DVI-D £104.99
Keyboard and Mouse: Coolmaster Octane Bundle £38.99
Fan: Corsair AF120 single £9.99
Fan Splitter for 2 Fans £3.66
Anti-static wrist band: Grounding strap £0.89
Since then I have added the hyper 212 evo and a Samsung 500 evo ssd.
The case is terrible, I would not recommend it, it was cheap at the time and had a dvd drive slot so I used it. The airflow is useless which is why I have the side panel open. I was wanting to get a Phanteks PH-EC416PSTG case to incease airflow. Inside the case atm I have one intake (af120) and a cheap outake fan that came with the case.
Temps on idle are around 50 degrees however I have no software that can stress test and record temps then, however in the past I have had to leave it too cool when the stuttering became too much (mostly when playing tomb raider on ultra for two hours)