Starting in mid 2004 production Range Rovers the CD changer connectors were changed from a 3 and 6 pin connector to a unique 10 pin connector. I suspect this is due to BMW charging Rover too much for a CD changer and they started getting them directly from alpine. As a result the connector is changed. To replace this 10 pin connector with the old 3 and 6 pin connectors is a straight forward process that involves simply purchasing a cable from a BMW dealer and swapping the pins from one connector to another.
There are a couple options available such as BMW P/N 84 11 0 141 978
Start by unplugging the car battery or removing the fuse for the CD changer. Once the Cd Changer is removed you will see the 10 pin connector.
Disconnect the two connectors by pressing the tabs on either side of the connector shown at the bottom of the above photo
Gently pry back protective cover to reveal pins
Using a small screw driver gently press down on the locking level at the same time gently pulling the wire. The locking pin will sometimes get caught on the next hole
Be gentle when removing pins
If pin is caught on smaller hole use the screw driver to gently press down to release pin
Once all pins are removed replace them pin for pin with the wires on the new 3 and 6 pin plug. Take note of the pin location on the 3 and 6 pin plug as they must be in the proper location. If you move 1 pin at a time it can help from your getting confused.
Note that the rover wire colors are similar but not exact.
The RED/Green wire = Red on BMW harness
The Brown wire = Black on the BMW harness
The White/yellow/grey = White on the BMW harness
Also Note that there are TWO brown wires and Two White/brown wires on the Rover plug.
You can use either white/brown wire.
With the brown wire just do not use the brown wire connected to the 3 pin connector as shown in the below photo.
Feel free to insert the extra wires back into the BMW 12 pin harness or the old 10 pin harness as they will not be used