Here is the information on 457 visas.

http://www.immi.gov.au/skilled/skilled-workers/sbs/index.htm

Has information on tax and superannuation, follow the links.

Not true. You can own a house in UK and be non resident for tax purposes.

I did say "probably"...

But if you rent it out you pay tax on the income

To get back on topic and to answer the OP - I think it's best to see where you want to be domiciled for tax purposes and then see an Aussie or Thai accountant.

RAZZ

Again you're confusing domicile and non resident tax issues.

He's domiciled in UK, but he's a non resident for tax purposes.

Domicile will only become an issue for IHT when he dies. Income tax is for the living.