jane matrix light 2 NOT suitable for 18 months

[mamaCam]

the matrix light 2 car seat by jane is marketed as being suitable for baby's up to 18 months old. but my little one is only 5 months (a fairly small 5 months) and its really difficult to get her in and out of it and she can't stretch her legs out properly?

has anyone else had this problem?

am I missing some thing?

is there some way to adapt the seat or did the manufacturers just lie?!

I had the matrix cup (preceder to matrix light but same size). Although I absolutely HATED the seat and am not using it this time around my son was fine in it until about 9 months - definitely not 18 months as advertised. But by then he was happier facing forward anyway.