new build, are the components ok?

Wait, have you already purchased the two monitors? If so I can make the build better:

PCPartPicker part list / Price breakdown by merchant

CPU: Intel Core i5-4670K 3.4GHz Quad-Core Processor (£155.94 @ Aria PC)
CPU Cooler: Cooler Master Hyper 212 EVO 82.9 CFM Sleeve Bearing CPU Cooler (£24.25 @ Scan.co.uk)
Motherboard: MSI Z97-Gaming 3 ATX LGA1150 Motherboard (£93.99 @ Ebuyer)
Memory: Patriot Viper 3 16GB (2 x 8GB) DDR3-1600 Memory (£105.59 @ Aria PC)
Storage: Samsung 840 EVO 120GB 2.5" Solid State Drive (£56.99 @ Aria PC)
Video Card: MSI GeForce GTX 770 4GB TWIN FROZR Video Card (£278.12 @ Scan.co.uk)
Case: Corsair 300R ATX Mid Tower Case (£59.16 @ Scan.co.uk)
Power Supply: SeaSonic EVO Edition 750W 80+ Bronze Certified Fully-Modular ATX Power Supply (£77.70 @ Scan.co.uk)
Optical Drive: Lite-On iHAS124-14 DVD/CD Writer (£11.09 @ Aria PC)
Operating System: Microsoft Windows 8.1 (OEM) (64-bit) (£79.89 @ Amazon UK)
Monitor: AOC I2269VW 60Hz 21.5" Monitor (£137.00 @ Amazon UK)
Monitor: AOC I2269VW 60Hz 21.5" Monitor (£137.00 @ Amazon UK)
Keyboard: Thermaltake eSports MEKA G-Unit Wired Gaming Keyboard (£92.33 @ Amazon UK)
Total: £1309.05
Prices include shipping, taxes, and discounts when available

Edit it how you like.

SethJPC put together a nice build. If your friend can squeeze his budget a bit, he may as well get an i5-4690K for about 13 pounds extra, since he'd be paying more for a Z97 series board anyway. I'd also go for a board that is SLI compatible, in case he wants to add a second card later. These cheaper boards probably aren't the best for SLI but he could at least upgrade his rig piecemeal, rather than having to get a new mobo right away.

If he doesn't want to get an i5-4690K, it might be worth going to a higher level, but older, z87 series mobo for a more balanced build, though he'd lose SATA express if he did that.

CPU: Intel Core i5-4690K 3.5GHz Quad-Core Processor (£167.94 @ Scan.co.uk)
Motherboard: Gigabyte GA-Z97X-Gaming 3 ATX LGA1150 Motherboard (£103.16 @ Scan.co.uk)
Motherboard: Gigabyte GA-Z87X-D3H ATX LGA1150 Motherboard (£105.59 @ Amazon UK)

The Corsair Vengeance RAM is good and the Corsair RM psu should be ok. The Corsair CX series psu's have a bad rep, so i generally stay away from their psu's, but the RM's are better I believe. You might want to check that yourself.

Yes the Hero is a better mobo. I was just suggesting something cheaper for his budget.

6 SATA ports should be more than enough, 3 would be taken (SSD, HDD, DVD/CD), leaving 3 left to add extra drives.

No the Gaming 3 does not have onboard wireless, you would need to bout a card for it.

Z97 has M.2 and some have SATA Express.
M.2 allows 10Gb/s transfer speed through PCI, something you don't need as you don't have flash based PCI storage.
SATA express allows 10Gb/s though SATA, which could be handy for your SSD though not necessary.

For a fan controller i'd get this, if only because it looks good.
Fan Controller: NZXT SENTRY 3 Fan Controller (£35.16 @ Scan.co.uk)

Fan noise can come down to fan design, speed it's running, or how clean the airflow is (sometimes the holes in the case that let air through can make noise). It's also a bit personal as to how much that noise annoys you. I've got 3x200mm and 1x120mm case fan and 120mm+140mm CPU fans blasting on max all the time and it doesn't bother me, and i use open headphones so i can hear everything around me.

Update: A higher quality z87 will be better for overclocking than a lower quality but equally expensive z97. Also I have added rubber O rings that act as dampeners on all my fans, which also reduces vibrations into the case and therefore noise.

Finally found this PSU list that i've been looking for
http://www.tomshardware.com/answers/id-1804779/power-supply-unit-tier-list.html
The 750w RM is tier 3, so not necessarily a replace immediately item, but not for serious OC'ing.

It's hard to say exactly what he will be able to OC to, as it can come down to the chip, mobo, psu and cooling and is somewhat luck of the draw. Even if you have the best parts, the chip can be an lemon in regards to overclocking. Also i've heard Haswell is a bit more difficult to OC but i don't have any experience with this as i've got Ivy. I just had a quick look on overclock.net and they got a stable 4.6ghz, so 4.4 should definitely be attainable, but I'm certainly not confident saying yes with the quality of those parts.

The Seasonic SethJPC is a top quality PSU. For serious overclocking the Haswell refresh would be the best CPU, the 4690k runs a cooler, but for a 4.4ghz, there wouldn't be much difference with the 4670k.

The 4690k is refresh, the 4670k is haswell. These chips shut down at 105'C, so anything below high 90's is safe, but my guess is you'll looking at around high 70's during stress tests and mid 50's during gaming.

When you are looking at fans, they usually say their max and min noise in dbA, and airflow in CFM, look for the highest CFM with the lowest dbA. As a general rule, larger fans make less noise, have lower RPM's and push more air, so bigger is better. Also the position of his case will have some effect, if it has side fans, it should be quieter if it sits on his left, rather than his right.

Side fans will keep the insides cooler, but certainly not necessary or no-one would buy windowed cases. Given the level of the components, i would say he's better off getting better parts initially, and adding fans later, but it really depends on how tight his budget is.

I wouldn't say it will run all games on ultra, but it will be high/very high at least.

I would get the Refresh. At base speed it is slightly hotter but that is due to it having a higher clock speed, when you start to OC it will run cooler. I know the Maximus VI Hero will support refresh chips, but i think it will need a bios update. I'm not sure what other z87 series boards support refresh, so you'd need to check their websites.

The 300r supports only 120mm or 140mm in all locations except rear exhaust where it only supports 120mm.

For 1300 pound, this is the computer I would build.

PCPartPicker part list / Price breakdown by merchant

CPU: Intel Core i5-4690K 3.5GHz Quad-Core Processor (£167.94 @ Scan.co.uk)
CPU Cooler: Cooler Master Hyper 212 EVO 82.9 CFM Sleeve Bearing CPU Cooler (£24.25 @ Scan.co.uk)
Motherboard: Gigabyte GA-G1.SNIPER Z97 ATX LGA1150 Motherboard (£118.76 @ Scan.co.uk)
Memory: G.Skill Ripjaws X Series 8GB (2 x 4GB) DDR3-1866 Memory (£58.55 @ Ebuyer)
Storage: Samsung 840 EVO 120GB 2.5" Solid State Drive (£56.99 @ Aria PC)
Video Card: MSI GeForce GTX 770 4GB TWIN FROZR Video Card (£278.09 @ CCL Computers)
Case: NZXT Switch 810 (Black) ATX Full Tower Case (£86.42 @ Scan.co.uk)
Power Supply: SeaSonic EVO Edition 750W 80+ Bronze Certified Fully-Modular ATX Power Supply (£77.70 @ Scan.co.uk)
Optical Drive: Lite-On iHAS124-14 DVD/CD Writer (£11.09 @ Aria PC)
Operating System: Microsoft Windows 8.1 (OEM) (64-bit) (£79.89 @ Amazon UK)
Monitor: AOC I2269VW 60Hz 21.5" Monitor (£137.00 @ Amazon UK)
Monitor: AOC I2269VW 60Hz 21.5" Monitor (£137.00 @ Amazon UK)
Keyboard: Cooler Master CM Storm Quick Fire TK Wired Gaming Keyboard (£72.48 @ Scan.co.uk)
Other: Rubber O-rings for Cherry Keycaps (£1.39)
Total: £1307.55
Prices include shipping, taxes, and discounts when available

The case is awesome, and usually a lot more expensive. Plenty of space to upgrade and no problems with airflow or cable management options. It also come with 4 case fans included, so there is about 15 pounds you save on fans. This case can fit every available cpu cooler or GPU currently available, and probably every radiator available too, but be aware that this is a very large case.
The mobo is of a reasonable level, and better for overclocking than the MSI gaming 3. It also has SATA Express, which is good for that SSD.
Only 8gb ram, but that should be enough for now and it is an easy part to add more later if you need to.
For the Keyboard, I went with something with Cherry Red mechanical switches, as these are the type I prefer, and red backlit keys to match the build. Some people complain that Cherry Reds are too light, but I only think this matters if you rest your palms on your keys. You should do a bit of research here though as some people also prefer a tactile response.
I also added a pack of O-ring dampeners to reduce the noise of the mechanical keyboard. I use these exact ones in my keyboard, and they have reduced the noise to equal or less than a membrane keyboard. The extra O-rings make reasonable dampeners for your case fans as an added bonus.
Overall I went for a case with a window, as all the parts are black and red, which i think will look pretty good. With this case you will probably need an 8-pin power extension cable if you want to reach the mobo power on the top left of the mobo through the back of the case. I'd recommend the Bitfenix Alchemy in red. While at it, you might want to also get a 24 pin extension, and two 8 pin PCIe extensions (I believe the MSI 770 takes 2x8 pins, but it may be 6pin+8pin, you better check). These wouldn't be 'necessary' but will look awesome. All up these 4 cables would cost about 40 pounds on Amazon UK, but you could probably find other suppliers.

All the cables you need come with the PSU, but there is an 8 pin power cable that must reach the top left side of the motherboard. In mid size cases this standard cable is long enough, but in the 820, this cable won't reach if you channel it though behind the mobo, so if you use the stock cables it has to come over the front of your board and doesn't look very good. I've attached a picture of my rig, the blue cable coming down from the top-left is what i'm talking about.
http://i.imgur.com/UXU5BPN.jpg

The rest of the cables should be fine for length, and if you just going to get black extension cables i would only get the 9 pin ATX cable, as the standard PSU cables will be black.

The cables i was talking about were these ones
24 pin atx
http://www.amazon.co.uk/BitFenix-30cm-24-Pin-Extension-Cable/dp/B004GH9I0Q/ref=sr_1_5?ie=UTF8&qid=1404208235&sr=8-5&keywords=bitfenix+alchemy+red
8pin atx/eps
http://www.amazon.co.uk/BitFenix-8-Pin-EPS12V-Extension-Cable/dp/B004GHB2M8/ref=sr_1_11?ie=UTF8&qid=1404208235&sr=8-11&keywords=bitfenix+alchemy+red
8pin PCIe
http://www.amazon.co.uk/BitFenix-45cm-8-Pin-Extension-Cable/dp/B004ULYYQG/ref=sr_1_13?ie=UTF8&qid=1404208235&sr=8-13&keywords=bitfenix+alchemy+red

Yes, the case has tool less bays and removable HDD cages
http://www.nzxt.com/product/detail/111-switch-810-case.html

I can't really advise you on a red mouse unfortunately. Maybe the Razer Naga Molten, if your into mmo/moba's.

Upgrading to SLI will definitely be worth it. It should get him running everything on ultra. I've got a single 770 now and plan to SLI in the near future, to give me that performance boost.

The cables are just to make it look nice. The only one i would say you definitely should get is the 8 pin ATX.

My case is a 620, which is very similar in size to the 820, but my PSU is different and may come with different length cables to yours. With the standard cables in my rig the 24 pin ATX and PCIe cables would just reach if routing through the back. If a had a second card though they would reach easier as it would sit lower. The cables are easy to add later in any case, so if the capital isn't available now, i'd pass on them till later.

It should run the old games. I've got heaps of old games on my rig. Baulders Gate, Ceasar 3, Commando's, Dungeon Keeper and a few others, they all work perfectly. Except commando's where the speed of movement is based on the processor speed so every thing happens in hyperspeed.

Good luck and have fun. It's going to be a nice rig.