I thought that MOL's business model involved all their aircrew being nominally employed in Dublin, and paying low Irish social taxes. After Brexit (and I'm not in favour for other reasons) it might be easier for the UK to make UK-based staff to pay UK taxes, as his competitors must do.
Remember also, the profitability of a route doesn't only depend on how full it is. It also depends on the average fare. 180 pax paying £9.99 and buying no extras does not work.