Hi Chris,
Leaving was hard on all, we originally left uk when kids were 16,14 an 12. First 3 months was difficult, next 3 easier then last 18 absolutely brilliant. Coming back was harder than going out. Kids now 18/16 an 14 and did not want to leave. But we moved back to old haunts and old friends which helped
However asked them all if they would do it all again answer was a definite yes. All want to move back when possible and it is probably only chance we now have is to go with them.
Re their education, Aussie qualifications are accepted here, my eldest into Uni no probs based on finishing school in Sydney. Second accepted into 6th form based on year 10 results from school, 3rd just fitted back in.
Finally, re location just be aware how hot and humid Queensland can get. We are Scottish and the weather in Sydney was perfect, but I dont do humid so good. Each to their own, we do miss it all badly
But please seek advice from others as well, we have friends who tried it and it didnt work out.