I imagine there will be no shortage of folks from the larger non-NATS airports willing to head to Brum for decent money - that's certainly what I've heard from my colleagues who've had interviews already. On the other hand, those current staff who are settled in the area with families will probably want to stay (as well as those who realise that if this change of contract is successful then there's no point in moving because there will be no 'safe' NSL locations to go to anyway).