My DD is just 2.5 but top centiles for height and weight. She is already over 17kg. We currently use a concord ultimax isofix which we bought to keep her rear facing longer and she was rf until 2 in this. It was our only option at the time for our small hatchback but its clearly not going to last much longer. We already have a concord HBB that was used by DS but she seems to small to be in this, although it is well padded with good side impact protection, I don't like the idea of her just with the car seatbelt holding her. I was looking online and found the xtensafix but then found it had been withdrawn. Are there similar options? TIA