I found it much easier to connect to the dome light cluster on the roof.
Dont remember which wire was connected to the accessory power, but it
is easy to check with the multimeter.
You will need separate earth
connection (none of 4 wires from the light cluster are connected to
but there is a convenient earth point above, next to the antenna.
This is 12DC, so i hooked one standard USB power supply for 12V and standard USB - mini USB cable.
Thanks for the informative reply. I have a piggyback fuse, and the camera runs on 5 volt so it comes with a voltage regulator which is why I want to put it next to the fusebox in the passenger footwell. It is the Nextbase hardware kit. Thanks again.