Where to earth hardwire kit

[CAW]

Hi

I have bought nextbase hardwire kit and manage to to slip the wire behind both wires and air bag in the A frame of passenger side. (Not strong enough to pull the A Pillar trim fully with that metal clip in place).

I have threaded the wire down the inner door by removing the rubber sill and was going to the side where the fuse box in the glove compartment.

My question ... should I attach the earth (black wire) to a metal bar behind the glove box on one of the nut bolt (not sure if it safe to do so) or attach it to the nut near the door after removing the trim near the bottom.

I need to free up my 12v Accessory Port in the central console so that I can charge my phone.

Any Advice would be appreciated

Thanks

Carrie-Anne