""Surely the baby was just gagging on the long leg rather than actually choking.""
In all fairness, the baby was chocking because it was stuck, an older infant would pull it out.
The baby was being supervised, so what happened can be described as chocking, because of the angle, the gag reflex was worthless.
That's why the Marketing needs to change, at six months you can leave them on the floor with some toys (whilst you put washing out etc), they shouldn't be left alone with Sophie at that age.
Pushing them in a parent facing pram, with the toy etc, it's fine.