Welcome to PIO Matt & Rach, sit back and relax, it's a long ride
It's good to have some doubts as to whether it's all worth it, they just help you resolve issues that may be worrying either of you then you can focus on the emigration process again... until the next doubt comes along! In that period you have time to assess and re-assess it all and make the right decision for you and the kids, whether thats to stay in Greyland (sorry England) or try Oz
We are still at the early stages at the mo and have no doubts it will be the right move for us and the kids, thats not to say 'fear of change' won't try and give us a niggling little doubt every now and again
Good luck.
Paul.