The only 2 things certain in life. Fortunately, the serving member can get a free will through ADF and if you choose to send off a P85 and move your wealth to Australia then there will be no inheritance tax.
The UK and Aus tax systems vary, the main difference for you is the tax-free allowance in Aus doesn’t change annually, as your ADF pay, allowances, UK pension or rental income etc increases, more of it ends up in higher tax brackets every year, negating the increase.
Here are the tax rates you will be on in Australia 26-27:
See an annual example of how overseas income ends up taxed at higher rates.
Using paycalculator.com.au you can add in your expected income, expected pension rate or other income streams (Just remember to convert to AUD)
On my arrival and personal financial planning, I thought along the lines of:
I will earn more than I ever have moving to the ADF, I could lose 30-45% of those extra earnings and my pension in taxes and never see that money again.
But…. By intentionally moving some of each pay packet into the retirement fund provided by the ADF. Majority of what I would lose in tax and never see again will instead be invested for my future and returned to me plus interest at 60.
In doing this, I will create sustainable financial habits early on my arrival in Australia and still have more take home pay annually than I used to receive.