First, it asked whether he had an existing on-account mobile plan, but didn't ask whether he had an existing landline/broadband plan (he does).
The next step asked whether to transfer broadband from an existing provider, order a new connection, or add a second connection. As fibre will require a new physical connection, we chose to order a new connection. However, later on in the process, the wording implied that that was the wrong choice.
At this point I tried logging into Customer Zone, in case an upgrade was supposed to be requested from there. There didn't seem to be an option to do this.
At this point, we went back to the signup page and chose to transfer from an existing provider. The next page asked who the existing provider was, and thankfully had an option for Vodafone. It seemed like we were finally on the right track! But then, towards the end of the process, it wanted personal details for a seemingly-needless credit check (the new plan is the same price as the old one and as far as I know it's always been paid on time).
We did manage to get through the forms eventually, but it took longer than it should have, especially considering the amount of backtracking that was needed. Is it possible for these forms to be tidied up, or at least documented a bit better?
PS. The Big Back Yard documentation still says TelstraClear in several places.