Well the nav system is up and running perfectly using v29.1 and 2007-02 dvd map disk.Thanks for your help.
Only problem is the volume control circuit on the display board monitor is faulty.When the volume is reduced to a low level the sound turns into a terrible noise. Rasise the volume a touch more with the volume control on the display or the steering wheel and the sound is returned to normal.
Anyone have any ideas please?