Liam, Did you get it working with Intel HD 4600 Graphics (4th gen) on win7? I could not find the drivers you seem to have. The 15.36 series drivers seems to be the latest to work with win7/4th gen. The newer 15.40 series for 4th gen is only available for win10.
I do have it working at 30hz. My monitor is a Sony XBR X830C (hint: had to use hdmi 4 to get it to do 4K).