Interesting. I did post this last week:
"The only thing that may give faint hope to some is that there are some quite big gaps between flights, e.g. 2h15 on a Thursday and 1h45 on a Saturday."
This suggested to me that a 4th aircraft could still be a possibility, as I found it hard to believe the aircraft would sit there that long. My hunch was that the aircraft would head off somewhere unpublished after 30-40 mins on the ground and another aircraft would operate the flights cited.