UPDATE:
Its been a while but recently i've started using my monitor again and not just my tv.
I was using the PC on the TV only through onboard HDMI. And
zero flickering/extreme-tearing!
I then moved to the lightning (the problem card) and surprisingly it was fine was quite shocked. I then went and started using my monitor again, U2711, and then it started again, flickering/tearing on both TV and monitor. And sometimes the mouse cursor would become a weird single character and the only way to get the normal arrow cursor back would be to 'switch user' on windows.
SO - the i've narrowed it down to the Display Port port. This is the issue I believe, I've since disconnected my monitor cable from the gfx card and my tv is fine and no longer tearing/flickering.
What to do now?