Hard wiring Ctek charger in to Tuscan

[R11ysf]

I am looking to hard wire the Ctek charger in to the Tuscan as the cigarette lighter has been temperamental recently. So I have the battery terminal connection which can be run internally rather than just off the battery. The positive is taken from the 80 Amp fuse in the passenger footwell, but where does the negative go?

I can see the massive earth in the passenger footwell but the bolt is far too big. I was told to take the earth from the door control until but I can only see a pin connector and not an easy earth there.

Has anyone done this before and can provide an insight please?

Thanks

[R11ysf]

Yes I just wondered if there were any other earths in the footwell? They all seem to bundle up and then run to the same big terminal. I managed to find an earth with a multimeter on the nut which takes the allen key bolt which retains the under dash panel but didn't think it was wise to use that.