Hello , advise re the autism assessment process

Hello , I have x 2 children who are autistic and a partner of 20 years who is diagnosed with adhd ( as an adult ) and has just had an assessment done for asd where he didn't get a diagnosis using an ados . 

For context my partner didn't talk till he was 4 or walk till he was 3 . He had no friends growing up as he found it too tricky eg he has one birthday party when he was 7 and he spent it under the table lining up his Lego in colour co ordinated  lines and biting anyone that touched it .... He had a statement of Sen at school in the 80's  but no diagnosis , he was eventually left in a pupil referral unit where he played snooker all day till he left at 16 . He can not read or write and is every way imaginable is identical to out 2 children . I am 100% certain that he is autistic however the clinician who did the ados said he has traits due to the good eye contact he gave and the way he communicated . 

my question is should we go private and request a different type of assessment eg a DiSco or just stop and try and accept that maybe we are wrong ..he could really use support in all areas of his life eg work but without being able say that he is autistic he's been very difficult for him and part of me doesn't want to question the vadilty  of an ados as I've been reading that they are very accurate and I doubt any medical professional would back a second option via the nhs ( he waited 5 years for this assessment ) . 

Thank you