Assessment - short notice

Having sent my claim form back a couple of months ago, the DWP has just phoned and offered me an appointment for my face to face assessment this coming Friday.

I agreed to the appointment and now realise that my daughter - who was accompanying me to the assessment - will be unable to attend as it coincides with collecting the children from school.

My question is: how important is it to take someone? Would it make much of a difference if I go alone (in a taxi)? My claim is a translation from DLA and to be honest isn't terribly strong medical evidence wise, so the assessment is ultra important in terms of whether my claim is successful or not.

Thanks.