[Garry74]

OK, no need for the screenshots as I seem to have it working. A few quirks to iron out though.

So in the end:

1. I had a setting wrong in MadVR for the colour. I had it set to Bt 2020, rather than Rec 709. 
   
2. Windows decided to behave itself regarding switching HDR on, when I wanted it off.
   
3. I had to reinstall the Nvidia drivers.
   
4. I had the refresh resolution set in the wrong place. Setting it in MadVR worked for me.
   
5. Using an adaptor for the DVI port, worked a treat for the sound.
   
6. My TV had overscan set on.
   
7. My TV has two modes for HDMI. I needed it on mode 1, I had it on mode 2. Which was causing problems with the HDR.
   

So thanks for all your help guys. Looking at the above it should have been so simple.

Now all I need to do is get the sweet spot of 23.976Hz as mine is currently way off. Skipping frames really annoy me.

Any advice? Custom resolutions?