kingbongo :
Eximo :
I don't think you will meet your requirements with that budget. That is the entry level price for a 4K monitor.
I just found this not sure if its any good?
https://www.alza.co.uk/28-samsung-u28e590-d2863728.htm?kampan=adeu_uk-pla-cpa_produkty_c_1006964_WH605e2&gclid=EAIaIQobChMIwPuf84W_1wIV5ArTCh0mnQ8eEAkYBSABEgKoXfD_BwE
That would be one of those entry level products. A TN display, it does not have HDR. If you want to prioritize gaming over viewing quality, it isn't a bad choice. But pretty much all decent TVs are IPS/PLS displays with good viewing angles and color (but slow response times)
The only HDR monitor I think is available is the Dell UP2718Q and it is £1800. A few more scheduled for release in early 2018. HDR is fairly new to the monitor industry, and not that old for the TV market. Not very many games support it either (though I imagine the XBox will require support in their ports, or have a way to emulate it)