do you have any advice about how to adjust from this very bluey unrealistic colour of image?
Several of the Adjustment Sliders do not cover the entire usable range of adjustment. To get the entire range, use the Value Slider: click-and-hold in the parameter field, and drag. As the User Manual points out (I'm referencing this not to make you feel inexpert, but to help you answer your question):
Value sliders: Double-click the value and type a number in the value field, click the left or right arrow, or drag inside the value field to set a value. Often, you can type a much larger number in the value field than can be achieved by dragging the standard sliders. When using value sliders, you can use a modifier key to make value adjustments in small or large increments. (Emphasis added.)
See if with the full range of the WB settings available you can "normalize" your pictures. Iirc, the auto-WB control is also useful in this situation. (Afaik, auto-WB is as good a proxy for "no WB" as you can get. I don't think you can display an image for a RAW file without a WB.)
Kirkby - thanks for the quick reply.
Didn't know you could drag inside a value field - that's helpful.
But being able to get different numbers on the slider isn't the root of my problem.
In a specific example I have two photos - one taken with white balance set to flash and the photo was with flash, where after a bit of tweaking to get the colour I want the temp slider is at 5000K (and tint 0). The second photo has my shooting error with interior lighting white balance but taken with flash. The two shots were taken from almost the same point of the same view (but different people in frame). The shot with the white balance error comes off camera horribly blue coloured. I can fiddle with the two sliders - I take temperature to 20000K and tint to 40 to do the best with it I can, and with those settings one of the two faces is approaching flesh colour but the wall behind the subjects (which is a light blue in reality) is now appearing light yellow in places. I just can't get a good looking colour effect no matter ow extreme the slider settings.
I may have phrased my question badly - as I totally agree you can't show a raw without a colour setting - so maybe I'm better asking to be able to use a different colour setting on the raw data rather than having to start with adjustments on top of my white balance mistake.
Given the two shots were in the same place against the same background and the same lighting (both with flash) it seems to me I ought to be able to get a similar colour effect on both and I just can't. To illustrate here are the two photos (the one on the left was shot with flash wb and in Aperture I'm viewing it with 5000K and 0 tint, the one on the right was shot with indoor wb and in Aperture I'm viewing it with 20000K and 40 tint and it looks terrible!)