Helen's Gruesome End...

[almh]

I agree. There's very little limit to what you can do on tv, but there is a limit to what you can show. In series 6

Spoiler: show

they torture Zaf, and they tell us that they can only recognise him through dental records. That could be a terrifying and traumatic thing to watch, even just seeing his body later could have been a step too far. But we never see his body, we are only told, not shown what has happened, so it's fine for broadcast.