As far as I know there has until now been no official announcement that Darwin will re-fleet with ATR.
I have however encountered informed rumours suggesting this to be true.
Presumably they can source ATRs quite easily from Nordic Aviation Capital who already provide some Saabs, but finding experienced crew may be more difficult, so this may be a "water-testing" exercise to see what volume of applications they get.
Hope they do not make the same mistake as Intersky who hired hardly any experienced ATR pilots and regularly ended up AOG due to minor failures as a result.
I would think PPJN is a good guide to terms on offer SSS but I cannot confirm that.