The temptation to soften the shadow was too much for me and I went against my policy of moving on to a new painting rather than rework an unsuccessful painting. As a result I now have a painting that is not quite as unsuccessful as it was though it has acquired a few new problems.
My printer is not working at the moment. That means that I was not able to print out a reference photo to refer to as I went back into the painting. I lost one of the spools of yarn and in doing so the composition, the movement through the painting has been compromised. On the positive side, the values are better and the shadow is more pleasing to me now that it has lost its hard edge. Color variations are still wanting. A new start on a new painting is in order.