Thanks for your reply Azefore, I've tried three different power leads. The one supplied, plus UK plug adapter, was terrible in respect of the flickering problem. It gave me about a 4mm band of flickering along the top of the panel.
This was much improved by a normal UK power lead. I have tried two of those, and this very thin line of flickering remains with both.
As for the power brick, that heats up to the hot side of warm within a few minutes. It would make a great hand warmer:)
Seems likely that the answer to my flickering problem lies either with the lead or the brick.
I've got brightness set at 80% by the way. I can't seem to enter the menu apart from choosing two settings. I haven't worked out how to move the sliders. Is there a trick to the way you use the buttons to make changes? On the whole though I'm finding the brightness ok, and I've adjusted the colour using Nvidia's tool, so that's acceptable, although still cooler than the Dell 2408WFP.
As I have said, I've contacted AW two days ago but no reply as yet. Not sure whether to ask for a refund before my 30 days is up. that seems drastic over such a minor issue.
I don't really notice it when I'm sat back watching a video or TV, but when browsing it is very irritating and draws the eye. Also, it may get worse.
So a bit of a dilemma. Maybe, as you say, someone else has had a similar issue. Thanks for your input Azefore