Interesting.
On a personal note, my DD was in the ‘bottom set’ for maths in year 1 and beginning of year 2. I hadn’t been told, until her year 2 teacher said at parents evening, but DD knew.
She was there based on a very early verbal assessment of her ability, the teacher asked her questions. She didn’t answer. However she was (and still is) very shy. So the teacher thought she couldn’t answer rather than she didn’t want to. She just though got she wasn’t good at maths.
After constructive discussions with her year 2 teacher, she was reassessed and moved up a set, then moved again. She left primary with a ‘level 6’ in maths.
She is in the top maths set at GS and about to take GCSEs. It’s taken years for her to shake the effect of being in the bottom set on her confidence in maths. What would have happened if she didn’t have a parent who was prepared to question (nicely) what was going on? Or if she didn’t have a teacher who was prepared to listen to a concerned parent?