Reason I had a black screen was sat nav drive was out, took a while for the system to reset to the blue screen
What do you mean "sat nav drive was out"?
I have the same problem - black screen when the Intravee is fitted- but have got sound through from the ipod. My Sat Nav doesn't work (no red light on the drive and nothing showing on the screen, but haven't had the car long and don't suppose I'll use the nav, so haven't investigated what's wrong).
Any suggestions on how to get the screen working it does work when the Intravee is disconnected?