What about trying to cut down his daytime sleep by an hour or so? I found with James if he was allowed to sleep too long during the day at daycare, he'd take ages to actually go to sleep in the evening (he'd just chat to himself in bed for hours) and I had a chat to his carers and asked them to get him up when the other kids woke so he only got an hour - that seemed to do the trick. He would sleep for around 3 hours if you let him when he was around 2 years old. BUT, that kid loves his sleep!!