"Instead of the switchboard you described (which still leaves the risk
of enormous equalizing-currents when one batt is full and the other is
empty and in that situation you bridge/connect them)"

re quote above: That's a worry as very often that's been the case .
I'll make sure I dont bridge them in the future. Would this also be the
case with the common battery isolator switches with a "1", "2", or
"Off" position? or have I got my wires crossed. hehe

I'm in Queensland, Australia. Lots of Sunshine. Don't know anything
about MPPT chargers.

Connecting directly to the house battery sounds like a good idea and
would certainly simplify things.

Thanks all.