I wrote CPUs and I meant CPUs.
New GPUs might not be all that interesting. In most games the RTX 2080 is about as fast as a GTX 1080 Ti.
RTX 2080 MSRP = 699$
GTX 1080 Ti MSRP = 699$
The RTX 2070 should be about as fast as the GTX 1080 and guess what, same MSRP at 499$.
MSRP hasn't been announced yet but you can probably take a guess and just looking at the specs the RTX 2060 might be slightly slower than the GTX 1070.

PCPartPicker part list / Price breakdown by merchant

CPU: Intel - Core i3-8100 3.6GHz Quad-Core Processor (£103.72 @ PC World Business)
Motherboard: MSI - B360M PRO-VDH Micro ATX LGA1151 Motherboard (£65.99 @ Amazon UK)
Memory: Team - Vulcan 8GB (2 x 4GB) DDR4-3000 Memory (£78.27 @ CCL Computers)
Storage: Samsung - 860 Evo 250GB M.2-2280 Solid State Drive (£64.76 @ Amazon UK)
Storage: Seagate - BarraCuda 1TB 3.5" 7200RPM Internal Hard Drive (£29.39 @ Aria PC)
Video Card: PowerColor - Radeon RX 580 8GB Red Devil Video Card (£214.68 @ Amazon UK)
Case: Fractal Design - Focus G Mini (Black) MicroATX Mini Tower Case (£42.96 @ Aria PC)
Power Supply: Corsair - CXM (2015) 450W 80+ Bronze Certified Semi-Modular ATX Power Supply (£47.99 @ Amazon UK)
Monitor: AOC - G2460PF 24.0" 1920x1080 144Hz Monitor (£129.97 @ PC World)
Total: £777.73
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2018-09-20 20:52 BST+0100
I chose a 580 because the monitor is on sale and got FreeSync. Without that deal expect an extra 70-80£. In that case he could get a different, similar monitor and 580 or 1060 doesn't matter anymore.
Get the 2.5" SATA 860 Evo, it's not listed on pcp UK but should be cheaper than that.
I didn't put much thought into the case so he can change that.

If he wants to spend the rest of the budget he could get a slightly better CPU (i3-8300) and/or 16GB RAM or a significantly better CPU (2600X) that will be of no use to him in most games.

If the monitor deal happens 1070 might actually be doable by shaving of a few pounds here and there. Or just changing the CPU.
https://uk.pcpartpicker.com/list/27CMyX
(remember with the actual SSD price it should be -8£)
B350 mobo could save another 3£ but let's be real here, manually updating the BIOS isn't worth saving 3£.
He could OC it and get about the same performance. He might have to check the QVL for RAM (anything >=2666 is ok) though because those CPU/mobo might otherwise not like it.
I don't recommend going with A320 because either he saves 5£ at the cost of having to update the BIOS and not being able to overclock while keeping 4 RAM slots or he saves 20£ by going with a shit tier 2 RAM slot mobo with the same disadvantages that'll make RAM upgrades more expensive (replacing sticks instead of just adding 2 more) and is truly shit tier.

Ok so destiny 2 144fps at medium isn't really happening because 200£ for the monitor and 400£ for a GTX 1070 doesn't really work out. Low might be doable.

If he's not in a hurry he should probably wait for new CPUs in mid October.
Otherwise I can try to come up with something now.

https://pcpartpicker.com/product/LwxfrH/trendnet-wireless-network-card-tew805ub#
or
https://pcpartpicker.com/product/k9ndnQ/asus-pce-ac51-none-wi-fi-adapter-pce-ac51
or
https://pcpartpicker.com/product/6Zs8TW/asus-pce-ac55bt-b1-none-wi-fi-adapter-pce-ac55bt-b1

Depending on which form factor and antenna you want.

#3010
Was answered via Steam.

#3011
Yeah, not exactly motivated because of that.

Just for TF2 you need neither.
You've also thrown your budget out of the window apparently.

#3012
Depends on what you need and what your router supports. n/ac, 5Ghz or not, any more fancy features etc.

So what is your question?

#3005
Any specific reasoning?
16GB is completely pointless for TF2.
CX 2017 is worse than CXM 2015.
100R only comes with one fan.
A320 doesn't allow overclocking.
I've posted how to do the BIOS update often enough. Or just get a B450 mobo.

I'm really not sure what your goal is. You've only made the build more expensive and worse.

The "stay away from headsets" is for people who don't want to pay more for two parts mashed together than what two separate, better parts would cost and don't want to have to replace both when one breaks (and they will due to the lower quality).

#3002
It's not necessary and not overclocking might simplify the build a bit.
Although not as important there might be new GPUs as well so it'd be a waste of time making a partlist now when it'll drastically change again.
Just post here again in 3 or 4 weeks in case I forget.

#3003
That's essentially a QX9650 downclocked to 2.67 GHz so not a whole lot. It'd be slower than any 50$ CPU you can buy today.

Maybe you should just move away from headsets because they're all shit.

#2999
I'm guessing no overclocking?
When are you going to build it? Probably new CPUs within a month.

#3000
http://www.teamfortress.tv/12714/pc-build-thread/?page=19#557
Higher PSU wattage than necessary is a waste of money and efficiency.

#12/#13/#16
See #15 and #17.
New CPU does not work with old BIOS. Can't update the BIOS without a working CPU.
Solution: https://support.amd.com/en-us/kb-articles/Pages/2Gen-Ryzen-AM4-System-Bootup.aspx
Or buy a B450 mobo.

Either do some research and figure out whether or not you want to overclock or just don't.

#14

The 2700X is a thing that exists.

Not really.
It's a budget cooler. The only thing it does really well is being on sale for 20-25$. It doesn't do that in europe and is therefore merely above average (because the average is a very low bar).

#15

Intel is not nVidia and does in fact have to compete with AMD.

#17
Nah, that's about it.

If you're not going to stream you don't need 6 cores. The 1600 has been succeeded by the 2600 already.
Also "an i7" could be many things, the i7-7820X is also "an i7".

The budget is more important because you'll need RAM and a mobo as well. Possibly a cooler.
You also have to decide whether or not you want to overclock (should you be able to afford it).

Maybe.

Crystal ball's down for maintenance, should be back up by the next blood moon.

Do you need/want more fps?
What a bit longer until the prices at least have chance to drop.

Look at MSRP.
Now look at the GBP exchange rates.
Now cry.