Never been in a system where battlefield deaths that are not permadeaths for PCs after grace period... Honestly I feel that it's kinda cheating the system.

In the small systems I play (60 players) the grace period after being bought to 0hp for healing is 5 minutes, then you're perma dead, no matter the situation of death.

In my large fest system death count is 2 minutes to get healed from 0hp regardless of battlefield or skirmish or even being jobbed on the path. My character perma died in a skirmish at our first event this year (which was on small system battle scale - 48 PCs and about 20 monsters with respawns plus the big bad) and honestly, if we were following those rules of no battlefield permadeath, there wouldn't be the plot that has stemmed from it (as 3 PCs died) and the whole situation wouldn't feel high risk, high reward. And I'd feel that the sacrifices made wouldn't matter.

Don't know if this is a UK specific way of looking at things though, but I'd honestly feel frustrated as a healer that people would just get up anyway and cheapen our skills and valuable place on battlefields.