Compulsory Relatives Questionnaire for Adult Autism diagnosis

Does anyone know if a relative questionnaire (RQ form) is compulsory for autism diagnosis, or have successfully navigated a diagnosis without it?

I recently self-referred to Tower Hamlets Autism Service (East London NHS Foundation Trust) and although their response was rapid they insisted I have a parent complete ‘The Relatives Questionnaire’ form in order to be processed. I was given 3 forms; 'The Cambridge behaviour scale' / 'The AQ' / ‘The Relatives Questionnaire' the first two I completed in full. For various reasons I was reluctant the 'out myself' beyond the recognised doctor-patient confidentiality so declined to give the diagnosis team the RQ form and going as far as stating I saw it as a breach of my fundamental "human right to privacy" (Human Rights Act article 8). I subsequently received the below email closing my application for diagnosis without any further discussion and discharging me into my GP's care despite my self-referral. 

I'm considering contacting my GP to request a second opinion referral to an alternative autism service who don't insist on compulsory RQ form. But it would be great to know if this is a universal requirement or if others have received a diagnosis without it?

I know it's not hard evidence but the 2018 "Are You Autistic?" programme on Channel 4 filmed two people getting diagnosis both of whom got it in person with no seeming need for a relatives input.

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Your re-referral for an autism assessment by THAS was discussed at our team meeting yesterday.
Of concern is the lack of any developmental information and your reluctance to involve your family or partner in your assessment. 
The THAS team are of the view that without any developmental history information from your family, school or medical reports from your childhood, or collateral information from your partner, the results of any autism assessment will be inconclusive.  We have therefore taken the decision to not progress any further with your referral and we will discharge you from THAS to the care of your GP.
If in the future, if you are willing to provide some developmental information or collateral information then we would reconsider a re-referral.
You will receive a discharge letter by post which will be copied to your GP.
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