This....my son, 13, is clearly neuroduverse, major sensory issues, meltdowns (usually in the evening after a day at school masking), always interrupts. He has visual stress, is exceptionally hyperactive (luckily he's sporty), but is in the bottom sets at school as just can't focus long enough. He holds grudges against anyone who has ever wronged him, has such a clear cut opinion if what he considers right or wrong.
I did start to go down the private diagnosis route, but the school's evidence just wasn't strong enough and I gave up. To be fair the SENCO did say "we just deal with the child we're dealt with on the day" so will try and support him if he's having trouble. But is a big school with children with bigger issues, so mostly his issues at school are largely ignored unless he really disrupts the class. But I know it means their academic expectations for him are much lower than they should be. He's as quick as anything, visual/auditory learner, but whiteboards and books don't work for him.
He's also seen pyscologists and counsellers over the years and I watch on as he fools them with his alter ego, the butter wouldn't melt in his mouth approach. None of them suggested we get an ASD diagnosis
His dad also is neuroduverse, as someone neurological, I eventually realised I could not live happily with his different approach to life. When I suggested to his dad he may have ASD, he flew off the handle, was highly insulted and that was the nail in the coffin for our marriage. I think if he'd accepted it we may have found ways to work round his quirks, instead he said he couldn't live with someone who thought he was "mental". No matter how much I tried to explain it was just because we thought on different plains, he was not willing to.listen. Subsequently his dad has never been supportive of my getting him diagnosed.
I am exhausted most of the time, relieved when my son behaves 'nornally', but always on edge expecting a meltdown. The other day he had a complete meltdown because his den, where he watches TV was too messy and he didn't know where to start with tidying it, so I had to help him methodically tidy it. His dad can calm him down as they have a similar approach to life, but I have my son 90% of the time, so his behaviour is down to me to manage.
....that just felt very good to get off my chest...a bit of therapy in my chaotic world with my son!