VZ inverter installation

[vhorlon]

Hi all. I'm finding a lot of confusing information about this. I'm trying to install a pure sine wave inverter under the passenger front seat of my VZ Commodore Wagon. I have the positive cabling from the battery coming through the passenger side firewall all good, but I cannot seem to find a negative earth/ground point to the chassis close to where the inverter is to be located. Are there any near this spot (closer the better)? If not, where would be the closest good earth point? Thanks.

[EDIT]
I suppose I could relocate the inverter to the floor under the glovebox and run back to the battery instead, but that's really not ideal as its more likely to get disturbed by passengers etc, and the ground cabling would be much longer than I'd like.

 

[grey_hawk]

Couldn't you use a seat bolt?

 

[Fu Manchu]

Seats are a good earth point. There is a dash harness earth point behind the passenger side trans tunnel trim panel. It connects the earth to the body and is part of the bracing for the dash assembly.