Where has the 6 hour delay figure come from?
Press reports state the flight was the Porter (PD) 444, last Thursday night
According to timetables (available on line) that flight is normally scheduled to depart Victoria (i.e.pushback or first taxi) at 2230 local time.
According to sources such as Flightaware the PD444 that evening pushed back at 2303 local...so a 33 minute delay...
It never got airborne and (looking at other sources) returned to the terminal about 45 min later..and was then cancelled (Flightaware again)
So either Porter have been extraordinary unlucky with a couple of flights recently or the 6 hour figure is incorrect.
If you are quick the flight (or what there was of it) is still available for replay of flightradar, and the times will be on Flightaware for a while so you can check it for yourself.