IME - what Starlight said.
It's all based on the idea that SN's are a 'nurture' issue.
Now, you wouldn't tell someone with Epilepsy or Parkinson's or MS that they had that disability because their parents needed parenting classes, would you?
So why do parents of DC's with Autism, for example, another neurological condition, get told this, and sent for parenting classes?
It grates on me, after 15 years, tbh.
And yes, I'm DOING the bastard parenting courses, again. Because it's the only way to start to access the diagnostic procedure here.
I went on the courses with DD. I obviously took something in, because DS1's development was normal-ish, precocious if anything.
But I managed to forget it all within 18 months (silly me...) by having a second DC out of 3 with the same issues. So I went on that course again.
And obviously, because I'm supremely stupid (or being supremely patronised...), I am having to do it again because I have had the temerity to have a THIRD DC out of four with the same issues.
Ignoring the fact that just because they can't yet FIND the genetic link, it's obviously there when my Dbro has the same issues too...
Sorry. Rant over. No, I don't think any sure start parenting group can be a match for, say, extensive SALT offered as soon as the delay becomes apparent, Portage, ABA, extensive physio if nevessary, ditto OT, any aids necessary being provided in a timely fashion, statementing and a supportive preschool, nursery or school...with a supportive SenCo and a supportive HT.
Less 'gate keeping' of funds overall, with early interventions AND ongoing support, would make far more impact overall on outcomes of DC's with SN's that any amount of Sure Start parenting classes...