@Andyw2100 I vaguely recall someone posting in another thread that a constant 12v power supply is again available under the front microphone cover in P85D. Of course, I'm rather skeptical since I don't see a reason why Tesla would make power available again in that location. Nevertheless, you might want to check anyway because it would be far easier than tapping into the fuse box for power. I have not looked for the wiring in my car myself since I would have no idea what to look for anyway.
Yes, I'm pretty sure that's what andrewket was talking about in his posts, including this one:
The easiest place to access 12v for cars below vin ~15k and then again starting around 55k is behind the plastic mesh where the microphone for the Bluetooth resides. Search here on the forums, it's well documented. I used this source for a blackvue camera in my 100xx and 635xx VIN model S.
That's the location I've been referring to as well. My questions have just been about the specifics of connecting there.