Having not read CAP 413 for a while (actually about 25 years) I've just down loaded it and I can't find reference to SOB unless it is intended to be in 3.31 under additional information.
While in the same job I posted about above I once had a doctor certify a thoroughly dead body dead whilst in flight. That created chaos. I had to go to the fatal accident inquiry to account for how the stiff had become stiff while in my care. I really struggled to keep a straight face as I explained about knowing the deceased was deceased before we took off, the fact that the quack signed the death cert in flight effectively made the time of death on the aircraft about 130nm NE of Aberdeen, and there was also the point that he died of massive head injuries, I admit some of my landings aren't the smoothest but...................................
SND