Building own PC (UK)

Hello! Maybe someone can advise on a custom PC build. One of my folks wants to build their own pc with a budget between 800-1,000.
I, honestly, have no much experience with building computers, neither too sure what parts to choose. They basically need a decent computer to smoothly play video games on and do some digital drawing. They sent me a screenshot of what parts they chose so far, but I am on sure so, perhaps there are some experts around to advise?

Screenshot of their chosen parts:
http://prntscr.com/1qevjsy

They chose those parts through pcpartpicker, but maybe there is another site where they can order parts and have already pre-built computer? As they have no clue how to build it either...

Looking forward to your replies