Mate , we moved here (Gold Coast ) from elstree over 10 years ago. Daughter was 5 at the time so it was the perfect time. Basically just fed up with life in London and then got caught up in London bombings so decided to make the move . (We had travelled here years ago so had some knowledge of the place , have you ?)
Australia is a fantastic place to bring up kids , great education system (in major cities ) , great climate and generally the Aussies love the way of life .
Down sides : like everywhere there are a number of rednecks who will rip you to bits for being a "pommie" and will abuse you relentlessly .
They have a massive chip on their shoulders for being in commonwealth so get used to being abused when anything goes against the Brits .
It is not cheap to live here ! House prices are good but day to day stuff isn't
They hate football (soccer !!!!) so get your arguments ready
You are a long way from family
Good things : strong economy .
If you want to work, there is work here
Lifestyle is second to none
You will enjoy the social life, they love just meeting up for beers and sport
Kids will thrive if they have already started the UK education system as it is a year or two ahead of here (but funnily enough it catches up around 12 years old)
My advice : do it if you are serious , it isn't a "suck it and see " move
Any more advice/opinion then PM me and I'm happy to talk direct about my experience