UK D600 oil/dust turnaround time
Just to quickly report that I decided, as it is getting near the end of the initial guarantee period, I would take my D600 in to Calumet, where I bought it, and let them see the spots that show up at f22.
The assistant had a good look at it with a loupe and let me see what seemed a spotless sensor until you held it at an angle and saw shallow marks - possibly oil.
I left it with them to send off to Nikon.
I think exceptionally promptly I got the call that it was ready exactly one week later. They had done the shutter replacement etc straight off. With a quick test, there are just a few marks. I will see how it goes. However, I felt I would like to have the piece of paper showing, the repair, just in case I wish to sell the camera.