Can't be assessed without an informant

Also, if you look at the criteria for a diagnosis here:

https://www.autism.org.uk/advice-and-guidance/diagnosis/assessment-and-diagnosis/criteria-and-tools-used-in-an-autism-assessment

the symptoms being present in childhood is a criterion so I assume that a memory of your childhood might at least be needed (although it's only an assumption).

I wonder whether the format of the assessment is relevant.

I suspect from reading this that I was diagnosed under the 'Disco' regime:

https://www.autism.org.uk/what-we-do/diagnostic-service/the-disco

"Where possible, information concerning the person's history in infancy and childhood should be collected from an informant who has known the person from birth. However, when for an adult, there is no informant available to give an early history, the items of the schedule can be completed for current skills, deficits and untypical behaviour"

"As mentioned above sometimes no informant is available. When this is the case the clinician has to obtain as much information as possible concerning the details of current skills and pattern of behaviour of the person. This type of dimensional approach to clinical description is far more useful for prescribing how to help each person than is assigning a diagnostic category. The dimensional approach is fundamental to The DISCO in contrast to other diagnostic schedules."

The diagnostic tools for the UK are listed here:

https://www.autism.org.uk/advice-and-guidance/diagnosis/assessment-and-diagnosis/criteria-and-tools-used-in-an-autism-assessment

Diagnostic tools for adults who do not have a learning disability

• Adult Asperger Assessment (AAA) – includes the Autism-Spectrum Quotient (AQ) and the Empathy Quotient (EQ)
• Autism Diagnostic Interview – Revised (ADI-R)
• Autism Diagnostic Observation Schedule – Generic (ADOS-G)
• Asperger Syndrome Diagnostic Interview (ASDI)
• Ritvo Autism Asperger Diagnostic Scale – Revised (RAADS-R)
• Diagnostic Interview for Social and Communication Disorders (DISCO).

Cinnabar_wing said:

All this makes it extremely hard on the person being assessed, especially if you are autistic, it is hard to communicate the distress caused by being messed around to an assessor.

Absolutely.

It can mean people not pursuing a diagnosis because it's painfully difficult to do.

It seems there is a big range in the people doing the assessments and their understanding of the guidelines/what their company policies are.  Some are understanding that it isn't literal or always possible, and if you can discuss things enough yourself, they are satisfied. Some seem to refuse unless you have filled out their specific form to the letter. I've never heard of requiring someone on the actual call before.

All this makes it extremely hard on the person being assessed, especially if you are autistic, it is hard to communicate the distress caused by being messed around to an assessor.

I'm very sorry Kool_kat , this must have been very upsetting, especially when they said it would be fine. I would contact the place again, and explain what happened and ask for an explaination, as you shouldn't have been told two things. I think there are places you can go, but you need the staff arranging it and the person doing it to be on the same page as to what they accept.

Bluelyn said:

but I did have someone who knew me fill in a report,

Interesting. 

I had zero input from another person. 

I've been assessed twice and neither time had someone in the call, but I did have someone who knew me fill in a report, I've heard of people having assessment without informate from childhood, but it can make it harder to confirm if signs as a child if you don't remember your younger years and what you were like then 

I am sorry to hear this and surprised. 

I was assessed via the NHS by a private provider without an informant but I do have a good memory of childhood struggles which may have influenced them.

I don't know the rules around this so unfortunately I can't advise you.

All the best.