Your white balance doesn't appear to be properly set; the entire image has a cool cast to it. What are you using to set your WB?
Do you not think that the blue cast might have something to do with the reflections from the walls? This, let me assure you is the second best lit room in the house with a large window in the wall opposite the sofa (see
view from sofa I have managed to get the green back by a combination of WB, slight desaturation and filters/colour channels). The Mamiya ZD also has something of a reputation for throwing green casts, not blue.
I am not convinced that it is a white balance issue because -
a, The blue is the same irrespective of the light source.
b, The problem cannot be corrected (or anywhere near) using the WB function in the Mamiya software alone, although it can help.
c, I have never had a major problem with WB with this camera before. In fact it's pretty forgiving on that front and colour temp is easily correcte.
d, The blue problem is only an issue when shooting these particular green walls. Here is another shot, same house, same day, using available light through a much smaller window. I will admit to having cleaned the colour channels in this one which has brightened it but not changed the basic colour. The walls are pretty much the right shade of pink/orange, if anything it's a little too warm.
I did not set a custom WB because it has rarely been necessary and any problems have always been easily sorted on the computer, which saves an awful lot of time, important with a budget to consider.
Justin.