@Neil Groves
Judge one thing: percentage of the image covered. Many manga manage censorship with at least one brain cell - mosaics, "magic light", anything but a big lazy black bar.
If more than 1/3 of the panel is covered, drop the panel. Faster.
Drawings aren't children. You don't call PETA when the MC guts a monster, you don't call Human Rights for a fictional victim, and you don't scream "DV/SA" across 99% of BL.
Apply the same rule here. I'm not pro child pòrn, but let's be clear: the only thing that's real is the censor's laziness.
If violence doesn't solve your problems, it's because you haven't hit hard enough.