My brother and SIL have 2 kids, one is 3years old and the other is 1year old. I am worried about the car seats they are in. In my car the 3 year old is in a high back booster seat (which i paid for myself, i asked them but they refused to pay, shes in my car about 10 journeys every week) the 1 year old isnt in my car at all, due to no space or seat. My dd also travels in my car in a forward facing isofix seat. In there car (3year old) is in a £7 halfords booster seat with no back and (1year old) is in a forward facing seat with no isofix probably around. £30? There car is brand new and has isofix. They see no point in paying over £30 for a seat as its too expensive. 3 year old also travels in the front with said seat. Ive told them that her seat is not safe as the seatbelt does not sit right and it offers her no protection from side impacts. Ive even went as far as showing them a crash test with a booster seat and they still cant see it! They think its fine but i cant get it out of my head, i cant stop thinking about how unsafe she is. My niece loves the seat in my car and keeps going on about how comfy it is and said she wanted one but her mum flat out refused. Should i ignore it and be happy shes safe in my car?