The builds already suggested are pretty decent and you won't go far wrong there. I differ when it comes to CPU and power supply, so I'll provide suggestions for those. Also RAM is coming down in price and I'll link to one about £50 cheaper than previously.
Power Supply: I suggest going for 750W. Some might say overkill but for a similar price it gives you options for extra storage and who knows, you may eventually go SLI....
https://www.amazon.co.uk/750w-G3-80-Modular-Gold/dp/B01M4NJSN5/?tag=logicaincre05-21
Great deal on RAM.
https://www.amazon.co.uk/Ballistix-Sport-16GB-PC4-19200-288-Pin/dp/B01DPSQPF2/?tag=logicaincre05-21
Just from experience on forums, Intel and Nvidia combination tend to see less issues, so based on that, this is a pretty decent deal.
https://www.amazon.co.uk/Intel-i7-7700K-QuadCore-Cache-Processor/dp/B01MXSI216/?tag=logicaincre05-21
As with all builds, you'll need to check that all parts are compatible. The CPU suggested above is compatible z170 and z270 motherboards only, for example.
How it all fits in the case, the air flow etc are all important too.
Also, there are some price falls on some decent GPUs right now. For example this, due on 30 December, which is only about £70 more than a 1070
https://www.amazon.co.uk/GeForce-GTX-1080-Turbo-OC/dp/B01M315CJH/?tag=logicaincre05-21