Thanks for your comments. I was already aware of fact that once lving in Aus you must register for tax and then you can inform UK tax that you are paying here so they do not double tax you.
I have details of migration experts in Brisbane (we met in York) and will be visiting them before we leave. What I really hoped was that posting here would put us in touch with someone who had been in similar circumstances and already moved out here to find out real experiences.
Most things on this site seem to be aimed at workers and I can understand that. I dont recall seeing any workers mention though problems getting trade qualifications recognised - my son in law is qualified in UK for work in refridgeration, air conditioning, mechanical engineering, electrical and handling of various gases. Not many can claim such a wide range but these are all recognised thoughout Europe. Before his visa was granted many questions were asked and documentary proof of all these qualifiactions had to be supplied. On arrival he found that he must requalify in each field if he wants to continue doing what he came out to do. eventually he got recognition in some areas after arguing his case but he still needs to call an electrician to deal with wiring and someone with gas certificate to deal with the gas in refidgeration units. Not quite so simple as he was lead to believe from the experts who helped get his visa. Sorry this sounds like a winging pom but not intended to be, just that I am concerned about assurrances given verbally that everything can easily be sorted.
I will be checking the other links you suggest, thanks.