If you are seeking help for your child/young person, it is always beneficial to have a parent(s) at the first appointment, for at least part of the session, to provide any relevant background and developmental information.
I will spend some time getting to know your child/young person, including finding out about their hobbies, interests, friends, strengths etc, as well as asking about the difficulties. I will be interested to know what are their best hopes from coming to see me and what they would like to be different in their life.
Your child/young person may be asked to complete some questionnaires as part of the assessment.
I would hope that by the end of the first assessment appointment, I will have gathered enough information that we could begin to have a shared understanding of the difficulties that brought you and your child or young person, and how we might work together going forward with a personalised treatment plan tailored to their needs. This would include what combination of people it might be helpful to meet with again, i.e. individual child/young person, parents on their own, or whether family therapy for the whole family may be appropriate.
Of course, following the assessment, there is no obligation to take up the therapy being recommended, and I will do my best to inform you about other alternatives available, including in the NHS.