Incoming from inlet connector outside of van goes into top of main switch / main rcbo.
Copper bussbar goes from LIVE at the bottom of main switch to bottoms of MCBs.
Neutral from bottom of mainswitch goes to common bar on the side of the unit.

Cables to circuits go;
Live from top of Mcb,
Neutral from common Neutral bar
and Earth from common earth bar.

Better pic?
http://www.ultimatehandyman.co.uk/co...split_load.htm

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