Have received &quart; inch copper rod to use as an earth busbar.
The idea is to run 2456mm of bar along the internal wall out to the earthing strip from roof to ground.
Then via a terminal block connect
a) 110v fuse box (4mm ~ 30A)
b) Mppt (16mm ~ 110A)
c) Invereter (4mm ~30A)
d) Neg side of batteries (16mm ~110A)