All done now. So here is the promised write up.
I will expand it once I get the additional parts such as TMC & Tuner.
Tools needed:
T25 torx driver (short shaft is best)
Torch
Stereo release keys (4 if fitting a nav unit)
Steps:
1) Remove both side under dash panels by removing the two screws underneath and the screws behind the dash end trims.
2) Remove old stereo and trim piece around hazard switch
Slide out climate control unit.
You will now see all the torx screws to be removed.
3) Remove the 2 screws at the top, 4 on the front and also there are 2 on either side near the back of the trim.
4) The trim will now pull forward allowing you to disconnect the electrical connections and remove.
5) This will now reveal the inner cage which is held in my a screw either side.
Remove the screws and the cage will lift out.
6) Now it's just a case of fitting new double din parts in reverse of the above.
7) Once you have refitted all the dash panels you will be ready to install the nav unit.
I have not got an aerial yet but when it comes it will be fitted up inside the dash.
One thing to note on the install is that the RNS-D required a 'safe' feed wire.
This was simply a wire linked from the permanent live to the safe connection as shown on the wiring sticker
On mine it was the red and white cable linked into the plug hole next to it.
Notes:
Don't tighten the new inner cage until you have lined up the outer trim.
When fitting the outer trim locate the base first and it will go back in a lot easier.
Finished result
All in all it is not a difficult or long job.
It's taken me about two hours and I have done that in the dark (only spare time I could get)
If you have any questions or would like extra help just let me know.