My DS (6months) has been asleep since 4.30 and is pretty fast asleep. He woke up a little bit at 5.30 but cried until I laid him flat so he could get back to sleep. His normal bedtime routine is 6.30 bath, lullaby, feed and sleep by 7. He has done this before in late afternoons and I have woken him up ahead of bedtime. Should I wake him up now or let him sleep?