OP
Knobhead
May I respectfully draw your attention to posts 1,3,4 and 8 Mr Tony sir, the installation appears to be of the single phase variety
Now why doesn't this forum have that nice 'poking with a stick' smiley? You'll just have to imagine it for now.
Looks like I’m not the only one to miss that. Like others I read L1 L2.
So the neutral currents are cumulative in this instance.