The delay between the discovery of the bodies and the 111 call

On the morning of the murders, Kaycee woke the neighbours daughter with prolonged barking around 7am, which was most unusual behaviour as she was not known to do this.  Robin didn’t have to leave for work as early that morning as normal, since he had a meeting with the SES in the city.  This could explain the delay between David's arrival at home and discovery of the bodies and the time when he rang 111: Robin arose later than his normal time and Kaycee's barking could indicate the time at which this occurred, a full 20 minutes after David's return.