Very interesting thread. I've worked at and been a parent gov at a special pre school up to and including reception age and I've seen how they really struggled to implement the montessori child led learning through play model with their children. It was particularly awful for those children with autism, who just delighted in wallowing in their stims. Those children 'on their own agenda' learnt very little. Conversely it worked really well for the more social children. The school eventually abandoned it for those children with autism and went back to a much more structured, adult led system. (But not ABA, obviously!) This was quite a few years before the new EYFS came into existence.
I later worked in a MS reception class which had embraced child led learning through play for 3/4 of its sessions. Again it was really successful for about 3/4 of the children. The child I supported just 'chose' to play on the computer all the time, on a really crap, repetitive 'educational' game. When I tried to encourage him to try anything different he was really reluctant, and I felt I had no mandate to insist. Other children had their favourite activities and spent most of their time monopolising them. The more timid or vulnerable children had no 'choice' but what activities were left.
It is too extreme IMO. It's a one size fits all experiment that just doesn't work for many children. My DS would have gained nothing from it. Any child with SEN in a MS school would be in serious trouble, either left out completely or dominating aggressively. My DS was much better off in a rigid, pushy academic school with very rigid structure (which was no fun for most DC) even in Reception. He actually hates Golden Time or party days. He had a split placement for his whole reception year, mornings at school, pms at the special school. It actually worked really well! Strict structure, jolly phonics etc in the am, old fashioned ASD SS using Pecs, getting OT and Hanen Salt, sensory food play, music therapy, RDA, swimming lessons, forest school, circle time, etc in the pms.
ABA sounds really good, but I just haven't come across it. I can see it would have worked really well for some of the dc who didn't seem to progress much at the SS. My DS turned out to be quite HF, so I do wonder if he'd have turned out ok with any sort of early intervention that improved his communication and hence behaviour. He certainly had a fantastic time at the SS!