Ginger, I don't think they're unsafe if used correctly, it's just that it's so easy to not fit them correctly. As far as why they are sold, I guess it all comes down to baby store profit But yes, you can buy one of those boosters (or there's a Hipod one that's highly rated too) without the harness. I got the Infa one for $125. Although check out how the seatbelt fits on the MR you've already got - if you're happy with the anti-submarining clip and the "fit" of the seatbelt around his neck, you would be fine to use it with the seatbelt as Olive suggested. The manual should show you how to convert it to booster mode.
here is the link to the latest CREP (Child Restraint Evaluation Programme) results...it mighthelpin your search for a high rating booster seat. there are some booster seats currently in the design and testing phase that will have harnesses higher than 18kilos so that they meet the new guidelines, unfortunately that doesn't help your present dilemma.
We have the Infa Vario Max and love it - super easy to use and the seat has an antisubmarining design so no clip needed. We had been using it with protecta harness but are swapping to adult belt. Be aware that often the baby shops have a company rep there to advise on seats so you should check the creps ratingMelbel posted and think about what will work for you best. xx
Car seats confuse me. I have W in an Evenflo Generations, it is harness up until 18kg and then used with the car seatbelt up until 45kg. So I am guessing that W will be at least 4 before he is out of the harness (which is no help to you lol). Then I think we use the car seat belt. But then the Australian car seat rules are very anal compared to NZ - we don't even need to have the seats anchored (but I do).
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