There are simply much better offers out there, North and South.
All the airlines are now struggling to get crews with experience. 20 years of diminishing t&cs, together with a much restricted cash flow for training just hasn't attracted the numbers of wannabes like we all once were(are!) And now a bun fight is starting with Emirates visiting Jet2 bases, and Jet2 doing exactly the same in Dubai.
Jet2 is a good place to work, but with a few small changes it could be a great place to have and finish a career.