Newbie, advice gratefully received

I'm not quite sure where to start. I'm a mum of 4. Twins girls nearly 16 are my eldest. One of the girls H has always had quirks if you like since she was small. There were lots of problems at home and pushed for some help via CAMHS. After very little help I was offered a diagnosis of an Attachment Disorder for H and then discharged. At this point H was around 5yrs old. Things progressed and we have had meetings with schools, we've had a family liason officer and recently social services involvement. Due to some of H's issues we feel that Attachment Disorder may not be the correct or only diagnosis for H and feel that she may be on the ASD spectrum but finding it incredibly difficult to get anyone to listen to us because H was given a diagnosis at around 5.

H shows very little emotion other than anger or frustration, anything that she doesn't quite know how to handle she will laugh at, despite how inappropriate.  She does not seem to have a filter whereby she can gauge what she is saying is offensive even if she doesn't mean it like it. She suffers from anxiety which she will describe as feeling sick. She doesn't have a lot of social skill when it comes to peers, she doesn't have any close friends and does not get invited to peoples houses or birthdays etc. On one occasion she was invited and wanted to go then didnt want to go because of her anxiety. We have had many problems over clothes with seams, too tight, too baggy, to girly then too boyish etc. We have issues with food whereby once she has something I cannot change brands, if I do change brands she WILL know even if she doesn't see the packaging she will tell on taste alone. We have issue with self harm like punching herself repeatedly. We have had issues with her saying she should be dead. H has been violent towards me and her siblings, H has trashed my house at times. H has always managed relatively well at school and has a natural amazing talent for drawing. H has a very big tendency to lie or embellish truths, for example she was told no sweets, she told school we starved her, H was told 10 minutes quiet time in her room she tells school we lock her in her room.

We really just want someone to listen, take our thoughts seriously, meet H and look beyond the Attachment Disorder diagnosis and see what they think. Does anyone have any thoughts or advise please. Many thanks from a very tired worn out mum who doesn't know where to turn anymore x