Being an appointee and the telephone assessment

Hi all,

I am my daughter's appointee, made the written application on her behalf. I have had a letter telling me the telephone assesment is on Thursday coming, 8am. Does my daughter have to be with me when I make this call? I stated on the original application that attending any kind of assessment interview would cause her overwhelming psychological distress. Can I assume that I may just do the appointment by myself? My dd is autistic and has severe social anxiety around authority figures, frequently either mute in such scenarios or regressing to the personality of an infant.
The letter states in bold, "You and the person who acts on your behalf (or somebody nominated by them) should both be at the telephone appointment. We wil call the person who acts on your behalf (or somebody nominated by them) first. If you cannot be with them in person, we can addyou to the telephone call. If only the person who acts on your behalf (or somebody nominated by them) is present, the assessment can still go ahead"
I am confused by this. On the one hand, they are saying we should both be present, and on the other, they say it will be OK if it is only me. My dd would normally be in a taxi on the way to her specialist school at this time of day, and no matter when in a working day they pick, it would cause her extreme distress to have to engage with a stranger, over the phone.
I would like to be able to tell her now, that she doesn't have to do this, and its not clear that this is the case. Can you give any clarity on this situation?