7 year old with very restless sleep - any ideas?

[MrsSG]

My DS has very restless sleep. He has a good diet, good bedtime routine, goes to sleep promptly on lying down (usually 7.30pm ish), wakes up 11 hours later. But in between, he flips around in bed, sitting up, turning round, moving his legs. Doesn't seem to be nightmares. No sleepwalking/talking/snoring, although he does often seem to breathe oddly ie holding his breath. All WHILST ASLEEP, apparently. It is worrying, because he wakes up unrefreshed and with big circles under his eyes. He is mildly dyslexic, and appears slow (slight stammer) and daydreamy, despite being quite a bright chap in many ways. The tiredness at the end of the day I am sure is connected to all his extra processing/effort as a dyslexic. But to START the day tired? But I am convinced the sleep thing is connected to the tiredness and fogginess. GP is doing bloods (in case anaemic or something) cos I was forceful, but she is very unconvinced there's anything wrong, and it's "just how he is".
Sorry -long post. This is also my very first post, so be gentle with me! Anyone had similar experiences? Ideas?

[mawbroon]

Could perhaps be sleep apnoea.

[SnowLondon]

If he goes to sleep straight away, maybe he is over tired.
Could you try a slightly earlier bed time. 7pm maybe?