This is defined by reference to "permitted activities" and the defence applies only where third party liability insurance is held in respect of the activities." and "The defence for airsoft skirmishing can apply to individual players because their purchase of realistic imitation firearms for this purpose is considered part of the "holding" of a skirmishing event."
This is defined by reference to permitted actions, and the defense applies only when third-party liability insurance covers those activities.  Additionally, the defense for airsoft skirmishing can apply to individual players because their purchase of realistic imitation firearms for this purpose is considered part of the "holding" of a skirmishing event.