I see todays flight has also been redirected(Gander again?).
What was the reason today?
It may be something to do with their ETOPS clearances, perhaps? If they've only got a basic level of ETOPS clearance and are having problems today with one or more of the en-route alternates being out due weather, then this might force a longer routing, hence requirement for a fuel stop.
...or I could be talking out of my behind...apologies to all at Jet2 for having unfairly done you a disservice if so!!