And last week, I have learned that when there is somebody giving details over the radio to the switchboard so that info can be passed on to 999 it is not obvious that other radio users should keep the airwaves clear beause it is more imprtant for a powerpoint presentation to be set up than for switchboard to be able to pass on to the emergency services that the person injured is conscious and breathing. It is always best to go on the assumption of no knowledge and no logic, then you can only be pleasantly surprised.