I'm such a nugget, tried 5 different cables, tried a different PCIe slot and still purple, in the end I gave up and ordered a 1050ti & 3 different HDMI cables from the rainforest for delivery tomorow (now canceled)
Thinking more of z10m's comment, I went back to the user manual and could'nt find anything in relation to his comment so tried a few settings on the tv and bingo there is a setting called "HDMI 2.0 Format" switched this and now working perfectly ... I guess my 10 year old HTPC lives on
Have set Emby up with MPC as an external player with the settings you provided Razor Time
Anyone with a 55U7A, the settings is System - HDMI & CEC Functions - HDMI 2.0 Format - switch to Enhanced Format.
thanks all for the help