Does anyone know if there are any small portable booster seats that are legal??? I have a tall 6 yr old and a mum from school has offered to bring him home after school if I need help... But I won't let him in a car with out an approved restraint.. But it's not worth the effort to drop off his massive car seat... Might as well go myself! When I was a kid there were small plastic little seat things... Does anything like them exist since all the new changes???