Not tried this yet, just wondering if anyone can think why it might not work?

Also, I have had pioneer video playing head units in the past that have only required grounding of the handbrake wire, out of interest, what happens if you only do that with te D3 and don't bother with grounding and switching the location of the mute wire?

If you only ground the parking brake wire, the video will continue to cut out while driving because the gyro will sense that the vehicle is in motion. So, in order to bypass that, you need to move the mute wire to the open slot beside it and ground it along with the parking brake wire. Be sure that the pin clicks when you move it to the new slot.

right, so its because it is also a nav unit and therefore has a 3d accelerometer which it also relies upon.

Great!

lucky I found this forum otherwise I would have wondered why the handbrakew wire grounding alone wouldn't have fixed the issue.

thanks again.