DS is in a specialist ASD base within a mainstream secondary school and can attend the mainstream lessons if he wants to/is able to - he is also able to leave and go back to the base if other children are being too loud/disruptive.
We've found that having some control over this is beneficial to him, and he's done well so far in attending many of the mainstream lessons.
We were fortunate in that we had a fantastic ALNCo (we're in Wales) in primary school who fought to get DS assessed for ASD quickly (we waited a year rather than the initial estimate of 26 months), and the Engagement Team were also excellent.
Outside of that though it was hellish. I spent hours phoning round different organisations just to be signposted to other organisations that signposted me. Actual practical help was pretty much non-existent - what we begged for over and over again was help with what to do when DS has a meltdown as they are violent, and we have had nothing, no help at all outside some information on NVR most of which we found we were already doing and none of which is much use if it gets to the point where you're being bitten and punched in the face because of something outside of your control.
CAMHS have been useless (I don't completely blame them I know the pressures they're under due to my job) - wouldn't do anything about a child with extreme anxiety who was constantly talking about wanting to die or killing themselves. Just getting the assessment was a fight, with the ridiculous requirement that we had to check out services DS wasn't even eligible for due to his age. Then when they turned down the initial request for an assessment they sent the wrong fucking letter and instead told us he wasn't accepted for ASD assessment (he was on the waiting list at this point), which was an awful moment - I have never seen DH so despairing and angry as when he saw that letter.
DH and I were both referred to the Primary Care Mental Health Service, where we were told in the face of daily violence from our child to try mindfulness. DH never contacted them again. I did and got six sessions of counselling, and the lovely lady I was talking to was so concerned about me during the sixth session that she got permission to provide an extra two sessions. Apart from that I was offered group CBT I couldn't get to, or if it was online it was during DS bedtime routine.
We've had a number of services involved with DS, all of them were lovely people, but ultimately got us nowhere, except to give us more to do and a lot of appointments to work around. Then everyone dropped us at the same time on the grounds of all the other people/services we had involved, so now we have nobody except the school. I should try to contact a couple of them - OT for example - but I feel permanently exhausted. I'm also going to be made redundant this year and will be involved with the wind up of the organisation I work for, and I'm worried about how DS will take that - and that's our life, everything is about considering how DS will manage with anything that happens. Even just a family meal out is all about how well DS is likely to cope in any particular venue.