We are flying longhaul to Singapore with Singapore Airlines with our 2 year old daughter in 2 weeks time. Its an evening flight departing H'row at 1830hrs. We plan to take our car seat on board as she has always slept very well in it during our car trips. Has anyone done this before? Also the practicalities of carrying a car seat within terminals once we clear security. Can't remember if there are trolleys in the duty free section. Any advice, thoughts?