My asus ROG rig idea

Ok, a few things: Understand that by chasing after ROG, you're definitely going to be spending a good bit more money than you need to. If you're ok with that, then go for it!

I changed a couple things in your build:

PCPartPicker part list / Price breakdown by merchant

CPU: Intel - Core i7-8086K 4GHz 6-Core Processor (£368.79 @ Alza)
CPU Cooler: Deepcool - CAPTAIN 240EX RGB 153.0 CFM Liquid CPU Cooler (£89.47 @ Scan.co.uk)
Motherboard: Asus - ROG MAXIMUS X HERO ATX LGA1151 Motherboard (£229.99 @ Box Limited)
Memory: G.Skill - Trident Z RGB 16GB (2 x 8GB) DDR4-3000 Memory (£193.05 @ CCL Computers)
Storage: Samsung - 970 Evo 500GB M.2-2280 Solid State Drive (£149.99 @ Amazon UK)
Storage: Western Digital - Blue 1TB M.2-2280 Solid State Drive (£173.25 @ Amazon UK)
Video Card: Asus - GeForce GTX 1080 8GB ROG STRIX Video Card (Purchased For £0.00)
Case: NZXT - Noctis 450 ROG ATX Mid Tower Case (£138.99 @ Amazon UK)
Power Supply: SeaSonic - FOCUS Plus Platinum 650W 80+ Platinum Certified Fully-Modular ATX Power Supply (£105.80 @ Amazon UK)
Operating System: Microsoft - Windows 10 Home OEM 64-bit
Case Fan: Corsair - ML120 PRO RGB (3 pack w/Lighting Node PRO) 47.3 CFM 120mm Fans (£79.00 @ AWD-IT)
Case Fan: Corsair - ML140 PRO RGB (2 pack w/Lighting Node PRO) 55.4 CFM 140mm Fans (£59.99 @ AWD-IT)
Total: £1588.32
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2018-07-21 19:40 BST+0100

First, I threw in the 8086k. Normally, I'd heavily recommend NOT buying this CPU, but given your budget, you want as much performance as possible. The 8086k ships with higher quality overclocking capabilities, and is basically guaranteed to hit 5Ghz.

For your storage, I went for the best. Normally I'd say the 970 evo is overkill, but it truly does bring the fastest speeds for its price. If you weren't looking for a crazy rig, I'd much more happily recommend something like the 860 evo instead. At this budget, there's absolutely NO REASON to go for a non full-SSD setup. Going with m.2 SSD's not only decreases the weight of your build vs. HDD's but reduces the amount of clutter considerably (given all you have to do is plop them in, no cables or anything of the sort).

I went with a higher efficiency PSU as well. Finally, for the fans, I would think that you'd want the lighting in your case to be uniform. The Corsair ML series has some of the highest quality lighting imo, so I got a triple pack of 120's (2 to replace the ones on your radiator, and 1 for the rear), and a double pack of 140's for the front. The fans are purely personal preference. Overall, you have an EXTREMELY good build. Just one thing to note: Intel and AMD are expected to release newer lines of CPU's within a year or so. This build will definitely last you, but if you can wait, there will more than likely be a good bit of performance to be gained.

Again, there are some incredibly overpriced things in this build, so if you need me to cut the cost a bit, I can definitely do so. Otherwise, this is one sick looking build.

EDIT:
Also, you might want to consider custom cables for your PSU: they add that finishing touch that makes every build look awesome. Check out cablemod for those.