Enabling HDR

Both my AV amp and TV are able to receive HDR but the menus to enable high dynamic range remain greyed out on both. I have bought a good quality 8k ready cable without any luck.
In the video menu for the Denon amp it says the settings are only available using video, network or USB. I havent got a 4k ready dvd player and dont want one as Netflix is fine.Dont use the Talktalk set top box anymore as the quality is so inferior to the tuner in the LG OLED.
Picture quality is outstanding so its really curiousity to see if HDR makes much difference-any suggestions to get it working?