Mmmm tricky one - I think you need to weigh up what your lifestyle style is ITMS!! Croydon North is lovely, lots of great schools, sporting facilities, close to shops and Eastlink etc. are easy to get to. As you said you would have the bigger house and land for the kids too!

Having said that, we moved from Burwood East - a bit different but we moved out to Heathmont, which for us was another 10-15 mins commute for DH, doesn't sound like a lot - however he hates it and really wishes we were able to stay closer in. We moved when the kids were younger though and we were relying on my parents a lot and do even now but as they hit school age that won't be as necessary. Increasing your mortgage will probably mean more financial stress as well for you as well as a smaller home. Maybe do the drive at a busy time of day and see how you feel about it, because it can make a difference to how you feel about getting to and from work!! Good luck - hard decision!!