Adding a horses health certificate to TOR application

I am trying to fill in the TOR request online. I am bringing my horses back to the UK and want to add them to my application. However I do not have their health certificates yet as they are not issued until they are due to travel. Do I add their passport numbers and provide the health certificate later. Or do I wait and amend the application with their details once I have the health certificate?

Hi,
If you are bringing more than one animal into the UK but do not have this information, you can still submit an application for your belongings.
If your application is approved, you can make an addition to submit your animal healthcare certificate or passport at a later date.
If you are making an application for a single animal only and you do not have any belongings to tell us about, you will need to have a certificate or passport before you start.
You cannot submit an application without this information.
Thank you.