My DS2 is 5 and starting Year 1. He had entered Reception on Blue band (he knew all phonics and alternative sounds then already) and wasn't moved up all of reception, when at home he was reading Orange-Turquoise books.
He really progressed a lot this summer, and has been reading Early Readers (Horrid H and Captain U) to me, to his brother and to himself. He's currently reading a Lime book with me.
I told the teacher about his progress this September. But she put him back on Blue. She had him read a Green book and said he wasn't reading fluently with expression and there was one word he didn't seem to understand.
He goes to tuition with his brother (his choice), and his tutors say he's reading is excellent and fluent.
At home, he read words like "experience", "muttered", "bellowed" etc. by sight. He knows the sound difference between "heart" and "heard". He understands what he reads perfectly, and retells plots with nuances and details. He just sounds a bit robotic at time, but sometimes at home he does a goofy robot voice on purpose. When he reads funny books the expression is there.
My DS1 with SEN reads very well but never with expression and he has been moved book bands regularly. His lack of expression was never an issue.
Him bringing back easy level boring Biff and Chip, has sunk my morale.
Last year he did well at reception on the emotional and social aspect, but he did notice that he didn't "learn" much new.
He's pretty 'laid-back', so teachers are quite happy to leave him alone, which I don't think it cultivates the right/growth mindset for him. I'm happy to do the extra activities outside of school, but I'd like school to acknowledge where he is and taking him further.