Peter,
I was just looking through the RZ manual and it says that when the Emergency Shutter Operation button is used that the monitor lamps in the view finder will not illuminate. But I seem to recall you saying that they were lighting on Saturday when you had the problem, I wonder if you were to set the Emergency Shutter Operation, remove the battery fire a few times with lever set to M. Then re-insert the battery and switch off the Emergency Shutter Operation would it "reset" everything?
As you know I don't have an RZ, but just thought this might work.
David