My dd is 7, GnT labelled (I think she's just bright not exceptional), and I've had my problems with the local school boring her and not challenging her at times (mainly year 1). I try to stay calm about it, just monitor the goings-on carefully (I try to show my face at school, and ask them all about their day, who they played with, what they ate, what they did in class, and don't give up too easily) and I try to detect and make up shortfalls at home, considering school more of a social outlet in the end.
I did get a bit annoyed with being asked to think of "extension" activities to add to her homework myself; I work, and not in education, how the heck do I know what to do, or find the time?
dd2 is about to start Reception, and is miles ahead of dd1 at the same stage-she's older, had better nursery, and has had big sis teaching her! Meanwhile the school has got less and less native English speakers. Hope she isn't the only one, but I have my doubts. In a way I hope she doesn't sit meekly getting bored like dd1 did, but I suppose she will just be punished instead of stimulated if she plays up.
I won't say anything to the teacher (same one as dd1 had and I like her) about the academic abilities because I know it will be obvious to her, and she really needs the kids to be able to dress and toilet independently to get on with teaching.
A teacher can tell silent reading over picture gazing surely? One good thing about independent reading is they can then teach themselves.