How much sleep should a 5 yo need ?

[largeoneplease]

DS2 has just gone into yr1.

He goes to bed at 7:30 sharp and I have to wake him at 8am everyday. I leave it as late as I can to have a chance of getting him to school on time and I can't realistically get him to bed any earlier.

He hardly eats any bread/potatoes etc, so I worry that this could be the cause of his tiredness.

DS1 at 5yrs old slept from 8pm until around 5.30/6am

DS2 at nearly 5 sleeps from 8pm until 9/9.30am (if I let him!) (oh and he often crashes out on the sofa in the afternoons too)