Well, the 3rd battery is in. Cost HEAPS more than what I was anticipating. But now all12v and extra stuff is coming off the new battery. The only thing coming from the car batteries is the 12pin plug and braking things. (Fridge is on an Anderson so it now also off the 3rd battery). They couldn't get the yellow lidded battery, so got the same size in a marine battery. Said it was the same but just for boats, and it has a blue lid instead.
Will take a pic when the sun is up, as it's still dark and cold out.
Funny enough, a certain group forgot to go and fix up the license plate, so I will be calling them this morning.
@dagree, I may be paying you a visit after all.