Ds1 gave up daytime naps about 3 months ago. It wasn't a gradual process - one day he was having 2 hours at lunchtime, the next day nothing at all. It meant he was going to sleep at about 6.30pm (7 at the latest), rather than nearer 8pm. It made no difference to his waking up time (6ish).
About 10 days ago he announced that he wanted a nap at lunchtime, took himself upstairs, and was soundly asleep within seconds. He has done the same every day since. He goes into a really deep sleep (for about 2 hours) from which he cannot be woken.
The problem then is that he is wide awake until 9 in the evening and won't go to bed. I've been bringing him downstairs so that he doesn't disturb a sleeping ds2. He then wakes up at 5am, but is very grumpy and overtired (which means he wants a nap - viscious circle).
IOf anyone has any bright ideas on how to reprogramme him I would be most grateful.