STELIOS is a shareholder now and apart from the occasional whinge has nothing to do with the running of EJ.
Longer flights such as a Cyprus flight will be tight on crew hours if delays are encountered therefore I'm sure they'd send a plane there and potentially tag a sort SXF on to the end of another flight (eg crew operates LTN-FCO-LTN, if they have the hours they could technically be asked, but not forced, to then do a SXF) subject to crew hours to operate a rescue flight.
There is a plane and full crew on permanent standby in LTN from early morning up until the early evening so it could be that this plane could already be doing another rescue flights.
As the end of the day minimising passenger inconvenience is priority for all airlines and it looks like this was no different. If you'd want a specific explanation of what went wrong then file an EU261 claim and all should be revealed.
That way both flights operate instead of one operating and one being cancelled albeit both flights are delayed. This way you get people where where they want to be and don't have to pay for 180 hotel nights. Makes perfect sense to me.
As a whole the SXF-LTN has a 'very low' delay index according to flight stats. However as it is the plane's last flight of the day then it is more likely to be subject to knock on delays throughout the previous sectors, as with all short haul airlines.
Very surprised that light refreshment vouchers were not offered. I've had much shorter delays and been given them.
No doubt itll be rubbished by the spotters and a few 'frequent flyers' with an EC Blue card on here, but that's how it is. Airlines as vastly complex organisations and with so many dynamics at play, things won't always go to plan.