For me, the deal would be we ALL go for the six months, or no-one goes. Six months is a HUGE amount of time in a baby's / young child's life, not to mention yours, just when things are about to change so dramatically. Not to mention cost of living here in Canberra is significantly higher then in brisbane, so you may not end up saving as much as you imagine - especially with the cost of two households to maintain (2x food, electricity, gas, fuel, etc).

But that's just me, and the deal I have with DH about work away. No point having money if our marriage and family suffer because I cann't cope on my own.