My 6 week old ds, although fine settling and sleeping at night (fatal last words!), will not do so in the day and only really sleeps for long periods in his car seat. For example he will fall asleep in the car on the way back from somewhere and sleep on quite happily for an hour or so when transferred to the house. However, transfer him to his cot or moses basket and he will be up in 10 minutes. While these long sleeps are great (I have another 2 ds's 2 & nearly 4) I am uneasy about his back etc in the car seat. Any thoughts?