I'm due my third in 7 weeks and have been looking, with no luck, at how to fit a third car seat in a car with the middle seat just having a lap belt. My oldest is 7 so she is in a booster which I think I can buy a new one that fits just a lap belt but I hate the idea of her being less safe than she is now as she uses the across body harness. I have tried desperately to find a company that will fit a different seatbelt in but can't find one. What do those of you with 3 children do (all buy people carriers??!!).