Isofix or not for car seats?

[Enigmasaurus]

We’re looking at 3 kids in car seats by the end of the year and have been thinking about an appropriate car for this (I’ve had another thread about that).

Speaking to some friends recently who have two slightly older children who are almost out of car seats, and they can’t understand why we’re keen to have isofix compatible seats. To me, it just feels more secure and safe in the event of a crash. They feel the data are not that convicing and that we are potentially spending a lot of money (buying a new car) that we don’t need to spend.

So, AIBU in insisting on isofix seats?

This one Britax Römer KIDFIX XP Group 2-3 (15-36kg) Car Seat - Storm Grey www.amazon.co.uk/dp/B01M8HHN0F/ref=cm_sw_r_cp_apa_NDukBbF4ZRG8X?tag=mumsnetforum-21

We have an axkid minikid for erf in dh's car (DS getting on for 4) and the Excalibur cozy n safe in my mothers. If you are using the 5 point harness in the Excalibur with a child over 18kg then the seat should be belted and top tethered only. I had a huge discussion with the company about it. You can use isofix when it's converted to a high back booster and the child is using the seat belt but not over 18kg with 5 point harness. The Joie Bold seat would allow you to do that though but I've found the harness difficult to tighten.

Polkadot that’s interesting that the manufacturers don’t make that explicitly clear. Hoping that DC1 will stay in the harness for a bit longer (he’s not likely to be at 18kg for a bit).

Enigmasaurus - there is a section for each weight range/belt option in the instruction manual but it's not massively clear when you buy the seat. I really wanted the extra security of the isofix whilst using the harness of the higher weight which is why I phoned them. I did want the isofix for when we convert to hbb so I know the seat is always secured. I'm so used to the Axkid seat which is really solidly secure in the car that I'm finding the forward facing seats have more 'give' than I'd like.

Just noticed that our Renault grand scenic has 3 isofix in the back, not a massive car either.

I have tall children and they all grew out of the harness height-wise before weight wise.