lougle, if it helps at all, we are coming to the same conclusion with our dd2.
all fine (apparently) according to her teacher, however I look at dd2 at work/play while in school and get a very different picture.
her teacher sees her playing with group of children. I look that little bit closer and see her playing (entirely on her own, inc talking to herself) very close to the group of children.
her teacher is impressed that she can do XYZ in class. I know she can actually do more, but will not volunteer this information as she is terrified of being wrong/doing wrong - she cannot cope with the idea of failure at all, whether that is her getting an answer wrong, or the fact that dd1 was better behaved when having her hair washed (yes, really!)
she is yet again getting hysterical at the thought of the things she cannot do in school - which, given her recent report was all 'is working consistently across the board at least two years ahead of her chronological age' is just very sad, tbh. she is constantly praised for trying, not achieving, yet she is still petrified of failure, while actually being ahead for her age. she cannot cope with us even praising dd1 for what (to dd2) is an incredibly minor achievement, without saying 'but I can do that too!' and floods of tears because we think that she (dd2) is not as good/clever/whatever.
we too, after a half term where it became clear she was struggling with some social aspects of school, are now thinking we need to get her in the system, to have that piece of paper for when the situation at school hits crisis (if it does, but it looks likely if they continue to not see her issues).
she is a dream in the classroom - highly organised, follows the rules, remembers everythig she needs to, etc etc. but I fear for when she leaves KS1, and the work gets harder, and the demands mean she is using more and more energy to just 'get by' - I worry she will not cope well at all.