CatalystGamez :
1.5TB HHD and 600 watt PSU
Cool. Ok, so here are my views on what you COULD do. I know you've done a lot of research, so this is what I would do if I was in your shoes. And BTW, I have no problem with the case you're wanting... it would probably last longer then everything else.
Scenario #1
The i3 build. Assuming you would upgrade down the road, or when it when it goes bad. It basically gives you everything you have listed. I don't know if it makes sense to spend as much on a CPU cooler as you would a CPU. In my opinion, it makes sense to get a solid one for less, and consider upgrading when you upgrade your CPU. And, again, everything can be tweaked. If you save on the CPU cooler for now, you also save all together, so it wont hurt your pockets as much to upgrade later... and this still gives you everything you have listed. I also couldn't find your Ranger model Asus mobo, so I chose one close to it. This is what you pretty much had listed, and saves you money.
PCPartPicker part list /
Price breakdown by merchant
CPU: Intel Core i3-4330 3.5GHz Dual-Core Processor (£97.14 @ Aria PC)
CPU Cooler: Cooler Master Hyper 212 EVO 82.9 CFM Sleeve Bearing CPU Cooler (£25.34 @ Scan.co.uk)
Motherboard: Asus MAXIMUS VII HERO ATX LGA1150 Motherboard (£142.80 @ Kustom PCs)
Memory: G.Skill Ripjaws X Series 8GB (2 x 4GB) DDR3-1333 Memory (£57.08 @ Amazon UK)
Video Card: Gigabyte Radeon R9 280 3GB WINDFORCE Video Card (£139.98 @ Amazon UK)
Case: Cooler Master Storm Stryker (White) ATX Full Tower Case (£89.99 @ Amazon UK)
Total: £552.33
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2015-03-12 17:32 GMT+0000
Scenario #2
The i5 build. Pretty much the same build... but with the i5 and the same and nVidia GPU. The i5 will give you more head-room for a while longer then the i3 would. So instead of upgrading CPU and cooler, just go with the i5 and upgrade your cooler when you feel like you want/need to. Unless you plan on overclocking, I think the CPU cooler chosen will do you well for a while. Especially with the case you're getting and the ability to put a ton of fans in it lol. This is the top of your suggested budget, and I think the best performance.
PCPartPicker part list /
Price breakdown by merchant
CPU: Intel Core i5-4690K 3.5GHz Quad-Core Processor (£179.99 @ Amazon UK)
CPU Cooler: Cooler Master Hyper 212 EVO 82.9 CFM Sleeve Bearing CPU Cooler (£25.34 @ Scan.co.uk)
Motherboard: Asus MAXIMUS VII HERO ATX LGA1150 Motherboard (£142.80 @ Kustom PCs)
Memory: G.Skill Ripjaws X Series 8GB (2 x 4GB) DDR3-1600 Memory (£51.60 @ Kustom PCs)
Video Card: MSI GeForce GTX 970 4GB Video Card (£259.99 @ Amazon UK)
Case: Cooler Master Storm Stryker (White) ATX Full Tower Case (£89.99 @ Amazon UK)
Total: £749.71
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2015-03-12 17:36 GMT+0000
As long you get the gist of where I'm going with my views on both builds, you can take both and tweak them to how you want. So there's my insight. Since you don't need a PSU or HDD/SSD, you have more head-room for getting some extra performance out of your rig. This is what I would do if I had your buget.