Ok finally solved.

My issue with MSI AB showing blank sliders is apparently in newer versions of AB they dont include the Atipdlxx.dll, or at least if you copy Atipdlxx.dll into the MSI AB program folder from an older version of the driver (I used 12.1 whql version) then restart AB with the unofficial overclock mode2 option it shows the sliders again.

With AB 2.2.3, amd 12.6 whql and the Atipdlxx.dll in the AB folder i can drag the slider down and set memory clocks to below core -150

Got the dll file from here : http://www.mediafire.com/?phl44hvned2pwab - just pasted it into the AB 2.2.3 folder.

Will post an update with power measurements.

kind regards