What time does your DS wake from his nap? I found with my DD that if she slept later than 4pm it was very hard to get her to sleep before 8. She now wakes around 6:30 (used to be 7:30 but the sun's getting up earlier these days!) and rarely naps during the day, but if she does it is usually only for 40 mins. Then in bed by 7:30, sometimes if she is very tired, bedtime is 6:30.