How to change the Accounting Ref Date
To change the Accounting Ref Date, go to Company > Details:

Click on Details, then select Account dates:

Complete the relevant fields, then Save.
Now you can go to the Filing centre on the company’s homepage (Filing > Filing centre) where the AA01 form will be waiting for filing:

If you want to Preview the form before filing it, pick it up under Filing > Company Forms > AA01:

The form can be downloaded, encrypted with a password:

Once completed the AA01 can be found in the Cloud Library (Documents > Cloud Library):