DH and I are planning on visiting friends/family to show off the LO when he or she arrives, i've been reading that you shouldn't leave babies in car seats for longer than 2 hours at a time, but what do you do for long car journeys? have a break for maybe half an hour and put the baby flat in its pram? sorry if this is a silly question, I'm a first timer so haven't got a clue about travelling with babies. Thanks!