Have I got everything I need for my pc build? Any other advice you can give me?

About your RAM.

Your CPU and MoBo both support only 2133 Mhz RAM, while you've selected 2400 Mhz RAM. I suggest that you also pick a RAM that is 2133 Mhz.
Your current RAM will work on your system but it's speed will be downgraded to 2133 Mhz and that in my opinion is a waste of money.

If you don't plan adding an extra 8GB RAM to your build then i suggest you get 2x 4GB RAMs, since 2x 4GB 2133 Mhz RAM is faster than 1x 8GB 2133 Mhz RAM.

A good comparsion 2x 4GB vs 1x 8GB: http://ram.userbenchmark.com/Compare/HyperX-Fury-DDR4-2133-C14-2x4GB-vs-HyperX-Fury-DDR4-2133-C14-1x8GB/3554vs3555

And a set itself: http://uk.pcpartpicker.com/product/kkL7YJ/kingston-memory-hx421c14fbk28

Edit:
So, i took some of your picked parts as a baseline and build a set for you.
Here is pcpp link: http://uk.pcpartpicker.com/list/N29wgL

And now an explanation why my build is more expensive and what you get from your money compared to your original build.

1. I switched out your MoBo to Z-series. Z-series MoBo will enable you to overclock your RAM and also adjust your CPU base clock timings for some overclocking. New MoBo also comes with 2 additional RAM slots (total of 4) for future upgrades. And since new MoBo is ATX and your case also supports ATX, you can upgrade your GPU performance by adding an extra GPU and running them in 2-way CrossFire mode. New MoBo also supports twice as much RAM (up to 64GB) than your original one.

2. Switched out your GTX 950 with R9 380 for a much better performance,
link to comparsion: http://gpu.userbenchmark.com/Compare/Nvidia-GTX-950-vs-AMD-R9-380/3510vs3482
and for the future ability for 2-way CrossFire if you decide to use CrossFire.

3. Also switched out your i3-6100 for i5-6500 for better performance in multi-core usage.
Comparsion: http://cpu.userbenchmark.com/Compare/Intel-Core-i5-6500-vs-Intel-Core-i3-6100/3513vs3511
If you don't planning to do much multitasking and/or don't want to overclock as much, you can keep your i3-6100 and save about £80. But if your main goal is gaming, i suggest you to get i5-6500 for much better performance in games.

4. Didn't see a CPU cooler in your original build. Added it just in case you forgot to add it. But if you have a CPU cooler or you're planning to use stock cooler that comes with CPU, you can remove it and save about £24. If you plan overclock your CPU by adjusting base clock timings then i don't suggest using the stock cooling.

5. Switched out your PSU aswell. New PSU is more expensive but it offers 620W which is well enough for 2-way CrossFire and CPU/RAM overclocking. Oh, new PSU is also fully modular.

6. Also put in 2x 4GB RAM to get you going.

7. You can switch out HDD back to your Toshiba and save about £6 but i've seen from my experience that Western Digital is more durable.

Oh, i didn't pick a monitor for you since my knowledge about them isn't good enough to suggest you one.

But as far as your original build goes, it's a good setup for today's gaming but it's lacking upgradability.