It is now working!
The issue I believe is something to do with Thunderbolt and USB.
According to this thread which were seeing the exact same types of messages in the log as I was seeing:
https://discussions.apple.com/thread...art=0&tstart=0
It turns out that removing the Thunderbolt display and then plugging the HIS II into the USB port did the trick.
I then plugged in the Thunderbolt Displayport and it also came on.
So I am writing this viewing all 3 displays!
FYI I always had the Thunderbolt Displayport plugged in never occurred to me to unplug it.