My dd (30mth) is rapidly growing out of her britax (9mth-4yr) as she is quite big built. We're going away next month so would like to get her a new seat as the car journey is quite long. Have looked at the babystart ones in argos but don't know much abou them. Due to car we can't have any maxi cosi ones as they don't fit. Any suggestions or advice greatly appreciated x