Confused about car seat reviews/testing - help!

[Llamasally]

Looking for a new car seat for DS either group 1/2/3 or 2/3. Looking particularly at safety Which , Mumsnet best buys and the ADAC testing sites all say something different for the models we are looking at. One MN 2021 Best Buy says ‘probably don’t buy’ by Which and only get 50% ish in their review. Help!! How do I work out which is right/ the best or most rigorous testing? Giving me brain ache..

*on Which

I bought a Which “don’t buy” 0/1 car seat. It had excellent crash test results, premium brand, fit my car and child well but the Which complaints about it were it was unsuitable for a tiny newborn (it probably wasn’t ideal for a newborn but my child was several months old by then so that didn’t matter to me) and it was too easy to install incorrectly (I didn’t intend to install it incorrectly, since I was capable of reading instructions). I’d want to know why Which marked it down before I gave too much weight to their views.

Why would you not know if you want a 1/2/3 or a 2/3 though? If your child is big enough for a 2/3 and outgrown the 1, why pay for the extra features, a 2/3 is much cheaper? And if they need group 1, they need group 1?

Reviews can be quite subjective as you don’t know what the criteria are. I’d look at the In Car Safety Centre and get some advice from them on the most suitable seat for your car. Look for ones that are Swedish plus tested and extended rear facing.