Yes someone did get back to me it is crushed blacks issue that I have as you say, he did attempt to advise me to try some settings to fix it (white balance points) but I could not find those exact settings.
I will have to keep digging and asking till I get some concrete answers, its quite possible my 42" C2 is faulty, I can't imagine black scenes would be that bad and pitch black but they are on my screen and maybe upping the black level a bit is not a good fix but no one else has confirmed it yet. Got 3 more weeks to figure it out at least.
Its a shame it was the flicker that was causing your headache, but sadly it does something effect some users they really do need to address these issues.
I find some games are perfectly fine at 1440p at the full 42 inches, especially if I'm sat back with a controller it can be hard to tell the difference between 1440p and 4K once you're back far enough (also you tend to forget once you've been playing a little while anyway).