First time car owner completely confused Group 1/2

[OneCarefulDriver]

We are buying our first car seats for our two children and are completely confused.

Elder is 3 years 3 months, weight 14.8 kg unclothed, well over 15 kg with clothes and shoes but not coat (advice seems to be that it's the clothed weight that counts), height 99 cm.
Younger is 2 years 4 months, weight 13.8 kg unclothed, 14.7 with clothes and shoes, height 94 cm.

The elder meets the weight limit for Group 2 but not the height limit for the same kind of seats in i-size and it seems that she shouldn't be in that kind of seat until 4 years old? So she should be in group 1 and have a seat that doesn't use the car's own seatbelt.
The younger I'm guessing should be in Group 1 until 18 kg or until he's too tall?

I've read all the ADAC data on their website and thought that we should choose from the seats with a better than 1.8 rating for safety as 'acceptable' doesn't sound like a ringing endorsement, but then that means several hundred quid or even over a thousand for potentially less than a year if the prices they give are correct. Obviously not keen on that but there's no other way, is there? Or have I misunderstood? Looking at some of the group 0/1 seats I can't imagine my toddlers fitting in them from the picture.
I've read on other threads that group 1/2/3 seats are a bad idea because they can't do everything well, I imagine the same goes for group 0/1/2 and 1/2 (if the latter exists, which I haven't seen.
(Not planning to rear face as I just don't see them accepting it now having never been in a car seat.)

What about a 25kg rear facing seat? These do rather well, and can last until average 7yo so very long lasting. I’d take a look at these

Low budget under £250
Britax two way elite
Axkid move
Britax MaxWay

Middle budget £250-300
Britax multi tech
BeSafe izi plus
Diono radian 5
Avionaut sky

High budget £300+
Axkid MiniKid
Britax MaxWay plus
Klippan Century
Klippan Opti-129–this one actually goes up to 32kg so very long lasting, although it does have a height limit of 125cm which is a bit

Axkid one—very expensive at £600 and only up to 23kg

Op if you are uk based try and get to halfords, they are still open and would count as essential. They will advise you.

It is it just as simple as going on height and weight, some seats just don't fit in some cars. Get them properly fitted.

I would show them some pictures of rear facing seats - ask them - they might surprise you! I used to find it much more fun to go backwards in the car.

But for the forward facing options, your eldest is in the window I would choose a 123 seat. Although they are not the safest option in general and I wouldn't advise them from 1 year old, they are the perfect solution for a child who just needs another 6-12 months in a harness, where it doesn't make economic sense to buy a Group 1 seat up to 18kg, but they are still just that bit too young to go into a booster seat.

If you have top tether anchors in the car you buy I would get either Britax Advansafix IV R or GB Evernafix - these get by far the best crash test results for 123 seats. My preference is the Britax - it has a better harness capacity in that it goes a bit bigger, and when you switch to booster seat mode you gain a crotch hook which helps hold the seatbelt in the correct position and it's a really nice booster, nice and tall and has a recline which is rare. Crash test rating is 2.3, which is still good. I'm not sure where you've got "acceptable" from as this is within the window for "Good" which is like 4/5 stars. "Satisfactory" is usually the next category down and is numerical score between 2.6-3.5.

If you do not have top tether, there are only two options I'd consider, these are Britax Evolva 123 SICT, or Recaro Young Sport Hero. Personally I'd avoid the impact shield seats, they treat crash test dummies well, unfortunately they do not treat humans well. Real world crash data suggests they are good at protecting the neck, poor at protecting the internal organs. Score 2.7 Britax, 2.6 Recaro. Again though the Britax is a bit roomier.

The other thing with the criteria of a score under 1.8 is that these all tend to be rear only facing seats, infant seats, or booster seats. The fact remains that a forward facing seat with harness simply can't get such a good score, because this type of seat necessarily places more strain on the child's neck. There are only a couple that do and they are all combination rear facing/forward facing seats which makes me suspect that the scoring is an average of how the seat performs in both modes (I've found some sources which say they test in all modes and use the worst score, and some which say they test in all modes and then compile an average.)

So personally, if I was picking a forward facing seat I'd instead have a criteria of under 3.0, although the lower the better of course.

For your youngest, you could go for a seat up to 18kg. You'd have a huge choice here including some which go both rear facing and forward facing giving you the chance to try him out rear facing and see whether he tolerates it. Or if you are set on forward facing, you can save money and space and go for one which doesn't rear face. These would be my picks:

Isofix, Rear/forward facing:
Britax Dualfix i-size M - score 1.9, about £290
Britax Dualfix 2R - score 2.1, about £200
(I believe these safety scores to be an average of the RF + FF modes so the "true" FF score would be lower, maybe around 2.4-2.7).

Isofix, forward facing:
Britax Trifix 2 - needs top tether, score 2.2, about £190
Britax Duo Plus - needs top tether, score "good" (too old for numerical, between 1.6-2.5) about £150 - NB - can also seatbelt fit, but performs less well, "satisfactory".)

Seatbelt fit, forward facing:
Maxi Cosi Tobi - score 2.6, about £130

However - curve ball - your youngest is on a higher growth line than your eldest. It may be worth imagining a couple of years in the future when your youngest is somewhere around his fourth birthday, likely a little before. He's likely to reach 18kg pretty much bang around this time, could be 6 months either side depending on growth spurts. Clothes and with shoes, easily 3.5. If you're going to worry about him in a seatbelt at this age, that means you're going to be scrambling for another seat, one which can harness up to 25kg. The bad news is there aren't very many on the market, at least not forward facing, they all but one need top tether, they also get poor results for safety (2.9 is the best performing one, most are unknowns, untested, cheaper brands) but on the other hand if you need a harness, then the worst rated harness is safer than an unsuitable booster seat. Rear facing seats are cheaper and test extremely well for safety, but don't give you the option to forward face. It may be considering either getting the eldest a 25kg harness seat for him to move to later, or getting the youngest Maxi Cosi Beryl to start with now. It probably won't get him right to 25kg, because the harness is short, but it should get him past the 18kg marker and it's one of the more solid seats - it got marked down, because the 6yo dummy's head pokes out the top, but that wouldn't be a problem if you didn't use it until 6. So I think the 2.8 safety rating, when younger children are taken into consideration is possibly a little pessimistic - it gets 2.1 if you look at frontal collisions alone (OAMTC separates side and frontal) which is actually one of the better forward facing seats on the market and particularly up to 25kg, is really good. It's pricier at £300, but you will get the use out of it, have the flexibility to fit with seatbelt or isofix (meaning it fits almost all cars) and it performs well with both thanks to the support leg. I actually think it's a great seat, as long as you're happy to forward face at 13kg and don't need to harness right up to 25kg.

ADAC prices aren't accurate, they tend to use RRP at launch, in Euros, in a country where car seats are much more expensive and have higher VAT. Use Google Shopping to compare current, local prices or something like PriceSpy. I would ignore the prices there and just look at safety ratings.

Sorry this has been really long, but hopefully it was helpful. I've certainly stayed up way too late trying to finish it :o

Thank you so much, Bertie Botts, that is really helpful. I will go and have the seats fitted, but I wanted to understand fundamentally how to decide what group to be looking at for each child so the clarity you’ve given is really helpful. I will take a look at the models you mention.
I was reading the info for the safety category only, as some of the ADAC ratings are ‘gut’ but then only ‘befriedigend’ for safety if you look at the subcategory.
Thanks again, lots more reading to do!

Ah OK yes, that's right. You will typically find this for forward facing seats as they just don't perform as well as rear facing ones.

OAMTC is useful if you want all the scores broken down numerically, which I find a bit more helpful than good/satisfactory/acceptable. But they don't have a full list of seats so you have to use the search by model name to find any you want to look at. Google Chrome can translate the comments for you.