I just wanted to report back about this monitor having owned it for a few months.
Short version: The best monitor I've owned.
Long version: After putting the settings as per the advice in some of the videos which have been linked to by some kind OCUK folks, I do not witness any more autodimming, the brightness is spot on and playback in games, video, desktop is just outstanding.
The real estate is phenomenal, I was worried I wasnt going to get on with it, but to be honest when I go to the office and use my twin 24" screens, the difference is day and night.