Can SKYWATCHER please verify if the times listed are "airborne" times?
What is the "source" of these times?

If these aircraft merely left their gates early, there is nothing in the curfew that restricts an aircraft from taxiing to the runway. Even if they start rolling down the runway at 0644 but are airborne at 0645 that is permitted.

As I've pointed out previously, ANY flight tracking website (eg: Flighatware.com) has a disclaimer indicating that "this data is for casual observation only and not for any operational purpose. FlightAware technology was NOT designed with the intent to observe safety or regulation anomalies, so please do not try to use it for that purpose."

Also, you are NOT abiding by their terms of use - Part 6 states - "You will not use the FlightAware web site for any aviation, commercial, operational, law enforcement, or judicial activity that relies on the availability, validity, or accuracy of FlightAware data."

Porter may very well have departed too early on those dates, but I suggest you wake up at 6:40AM and get a time confirmation from the control tower because that is the clock that is being used to determine the end of curfew hours. Then, with that synchronized watch, IF you observe an AIRBORNE aircraft PRIOR to 0645, then write down the flight number.

I've stated on numerous occasions that a 1-3 minute violation - while still a violation - should be accommodated for LATE ARRIVALS because, once airborne, any number of factors can add 1-3 minutes to a flight. The point is, has Porter or any carrier, made a legitimate attempt at operating within the curfew limitations? When they land at 11:20PM, the answer can only be NO. The same can be said for these possible early departures. There is NO reason to depart prior to curfew but they can certainly taxi to the runway and be airborne at 0645.

Take Care!
Joe