We took DD1 (now 13,yr9) out of selective private at the end of yr6, to start at state comp for yr7.
One of the reasons was bullying by some the teachers.
Strangely, once the notice was given in, all the staff started being extra nice to her. Almost as if they had never meant to push her over the edge.
Her final report was one of the best she had in most subjects. But there were a few nasty undertones that I feel would not have been there had she been staying at the school.
I don't know if the report ever got to her secondary school. But I do know thet her SATS results did not. As a result, she never had any FFT levels, And no end of KS3 targets until the start of yr9. Whenever she has questioned the current school on this, they have always said there was no information from her previous school, as she was the only one to have come from her previous school.
Looking back now, approaching the end of year 9, I think the lack of info was a good thing as it gave her a fresh start.
If you are going for a selective secondary school. then the reports may be important. But surely that would have been at the start of the application process, so would have been end of year 5.