Do I need to pay CGT in UK again for selling my AUSTRALIAN property

Hello I am a UK resident and have dual citizenship with Australia. I'm about to settle on selling a property in Australia next month. I'm also due to complete my self assessment form for Apr 22/23 FY by January 2024. I have a few questions if you could help me out. 1) Should I include the sale of the property in the self assessment form due January 2024? Or would it have to be following self assessment year, given settlement of the sale is December 2023? 2) Also if I didn't want to wait until the following year to include in my self assessment form, could I fill in this form anytime after the sale has completed? https://www.gov.uk/report-and-pay-your-capital-gains-tax/if-you-have-other-capital-gains-to-report 3) As I don't pay Australian CGT until the end of their financial year which takes place in June 2024. Therefore there is a possibility I would be paying the FULL CGT in the UK (when filling in the CGT portal), and then in Australia (July 2024). Would I then be able to claim the double treaty tax credit in retrospect after? Alternatively, if I paid CGT in the UK in full, would Australia give honor the tax credit their end? 4) What is the timelines typically of when tax credits are paid back as I'm hoping to buy a property in the UK with those funds/credit. Thanks.

Hi Joe Romeo,
As a UK resident, disposing of an overseas property, you are required to report the disposal in a Self Assessment tax return.
The date of completion of the disposal, is used to determine the tax year it is reported in.
 If the completion date is on or after 6 April 2023 to 5 April 2024, it would be declared in your 2023 to 2024 tax return after 6 April 2024.
 You would need to convert all the figures to pounds sterling, to include on your tax return.
The exchange rate is not set in stone, which is why you have a choice.
Under the terms of Self Assessment, we do not provide an official exchange rate and the onus is on the individual to use a just and reasonable exchange rate for each acquisition and disposal.
For your convenience, there is a choice of exchange rates here:
Exchange rates from HMRC in CSV and XML format
Or from another source, such as the stock exchange
There is a calculator in that should help you work out your gain:
Tax when you sell your home
Thank you. 

Thanks for your reply. Are you also able to confirm if I'm able to use this portal to report the gain instead of the self assessment form? https://www.gov.uk/report-and-pay-your-capital-gains-tax/if-you-have-other-capital-gains-to-report Also with regards to this link https://www.gov.uk/tax-foreign-income/taxed-twice - it states for property I'll need to pay CGT in both countries and get relief from the UK. Can you confirm the timelines/how long it takes for this relief to be reimbursed to me?

Hi
If you have no other reason for a tax return, yes you can use that link to report the gain.
When completing the form, you are asked if tax has been paid abroad and enter the amount paid (in sterling). this is used to set against any UK tax that is due.
It is not refunded.