Brian-BMW,
Thank you for your VERY quick response!
Since my post (& before I read your reply) I have powered down the car, disconnected the battery (neg first then Pos) & left it for 5 minutes then reconnected. Still nothing.
Red power light is on but Computer screen stays blank/black.
Before the power down I briefly got a light blue screen with all the functions, except Navigation, showing but as I turned the selector knob to the SET position the screen disappeared never to be seen again!
Does that infomation help at all?
Is there any way of checking if the MkIV unit is a monochrome one or not or definately needs re-coding as I could always return the unit to the seller.

Thank you.

Riggers
Range Rover Vogue 2002