We do now. Dd2 has cp, which has obv always been noticeable, but ds1 was different kettle of fish and only dx just before he was 10.
I would concentrate on the struggle to motivate if I was you. They essentially let Ds cruise for five years because they knew he was theoretically capable of the work, even if he wasn't coming up with the goods. (his y2 teacher nearly killed him during y2 sats, and mostly they resorted to the HT standing behind him if it was essential he produced at any given moment, to try and keep him on task). But I would fish for potential reasons for lack of motivation. Does he not want to do it? Is he bored? What does motivate him (I loathe this question and would be a rich woman if I had a pound for every teacher that asked me that, but might be worth you asking them?) is he just highly distractible? Is he easily led/ impulsive? (to a greater degree than his peers, at 6 really I'm not sure if you could tell!)
Essentially I would be looking for ADHD type behaviours, but also with a mind that gifted kids can appear similarly - there is an interesting book misdiagnosis and dual diagnosis of gifted kids - it's worth a read to give a few ideas, rather than point in you any specific direction.
I think it's also worth noting that until the issues cannot be put down to maturity (so probably by about 7 or 8) it might all be a bit of a guessing game. Are they providing stimulating and challenging work? Lots of gifted kids make mistakes with easy stuff because they aren't concentrating, and also because they have so much going on in their heads at he same time... When Ds had his assessment, the psych said he wrote everything for the maths papers on one sheet of paper, just writing in every tiny space he could find. She said it was a freakishly bizarre picture of what the inside of his head looked like - gifted and ADHD, scary place!
I think at 6 I would still be heaping lavish praise on the teachers and senco and begging them for help, and asking for their advice. Not because I thought they were particularly able or knowledgeable, but just because it makes them more likely to try and find some solutions that work. So lots of ' i really value your input' and 'what would you suggest?' if you flatter them enough to come up with some great ideas, they are pretty much duty bound to put them into place... ESP if you say 'oh, that's a great idea for the iep!'
I know it's a leeeetle bit dishonest, but needs must, and all that. Clever kids are often overlooked and not given support because they can do the stuff, they just don't.