Had a very informative call from Jez late on Friday, guess I should have posted earlier but I was away! Ok a few points (let's see if I can remember...):
Banding: Totally fixed with new firwmare
Green snow: In his own words they have no idea what the cause is, they tried 3 things (firmware, shielding and changing cables) and neither worked. They said that they were working over the whole weekend and hope to have some good news. They said for people who are temporarily solving the issue with different cables e.t.c, once they know the exact cause they would rather fix the problem than have customers put up with a fix. Remember, this was on Friday, so since then they could have found the fix.
Backlight luminance: The new firmware reduces the backlight luminance so we should be able to hit from ~180cd/m² to ~125cd/m² by default (trying to hit the target of 120 but obv screen dependent). This is done by reducing the amount of power the backlight uses, hence reducing it's luminance and allowing us to hit darker blacks.
Firmware: The RGB sliders problem is a bug which was an anomaly. He said this was totally unacceptable and will be fixed with others.
Future revisions: There will be a revision of the 24" and 26" monitors in around Feb, which will allow us to modify backlight luminance ourselves (amongst other fixes which I've forgotten).
Uneven colours (problem that I'm having where to get a neutral colour I have to set reds around 10 less than greens and blues using the OSD sliders): It's a common misconception that having all values at the same setting will result in a neutral picture, instead all values are independent of each other. Having said that, going to an extreme like I'm doing may imply a problem which they'll look into.
Overall Jez was very friendly and helpful, talking to him made me feel that they really know what they're talking about and want the customer to have the best screen possible. He even said on their new website they'll be talking about the drawbacks of S-IPS panels so that customers know what to expect, so they seem like a really honest company. Now the only problem I'm having is wondering whether to wait for the revised model, so I'll see what the firmware update can do!