We just bought a Honda Odyssey (YAY ). Get home this arvo, DH pretty sure the car seats would fit (1 x safe n sound rearward facing, 2 x maxi riders). We used to have a ford falcon and the 3 x car seats fitted in their AOK.

Anyway, they dont fit . DH says we need to replace the maxi riders with new car seats - but i dont want too. I think the maxis are sooo safe, and besides the fact i have $800 worth of car seat sitting there doing nothing, I dont want to go out and spend more money on car seats.
I guess what im asking is, if we replace 1 x maxi with a booster seat for 4.5 year old is that safe? What is the safest brand?
I dont want to compromise on safety but feel i am.....oh gawd.......

Suggestions ??