Here are some guides to help you through the relocation process.
And you can use the new TPG APP - https://www.tpg.com.au/download
There can be up to 30 days for relocation's to be processed.
There may be some overlap when one service may be cut off before the other is working, or the new one isnt quite ready in time.
This is out of TPGs hands, and more in the hands of NBN or Telstra.
Maybe starting your relocation process 2 weeks out would be a good balance.