I'm sure others will link elsewhere but I found this a useful resource when building mine: https://uk.pcpartpicker.com
I would say £1k would be plenty depending on what you're looking to play and at what resolution. But do factor in peripherals like a monitor, mouse, keyboard and sound (headset or speakers)
That site it great. It tells you what is compatible and will tell you whether the PSU you're buying is enough to power all the components you have selected.
If you were to go on for example Overclockers.com forums, that is what everyone there uses for speccing their PCs.
I'm sure others will link elsewhere but I found this a useful resource when building mine: https://uk.pcpartpicker.com
I would say £1k would be plenty depending on what you're looking to play and at what resolution. But do factor in peripherals like a monitor, mouse, keyboard and sound (headset or speakers)