Recommendations for stage 2/3 car seats

[INeedACheeseSlicer]

I need to buy car seats for my 2 DC. We have never had a car before, so haven't really paid much attention to car seats - we have been using Trunki boostapacks so far, but obviously once we have our own car we need proper seats.

DC are 8 (127 cm tall) and 4 (115 cm tall).

Is Isofix a good idea, or not worth paying for? I was thinking it would be better because then the seats wouldn't slide around in the back when they weren't occupied, but they seem a lot more expensive - do they have other benefits?

Should my 8 year old be on a high back booster or just a booster?

Can anyone recommend any particular seats? I don't want to spend loads on a name if something else is just as good but cheaper, but equally I don't want to compromise on safety.
There just seems to be a bewildering range of prices and seats available .

I'd say high backed boosters for both, and I don't think there is any advantage to having ISOFIX on a high backed booster other than (as you say) it will stop them moving around the car when your children are not in them.

It's not so much the seats sliding around that's the problem, it's them being thrown around the car in the event of a crash. All you have to do is fasten the seatbelt across an empty non-ISOFIX high backed booster.

Thanks for your help. Actually now thinking that having isofix would be less hassle than running round fastening belts over the seat every time the DC got out.

Does anyone have any experience of, or thoughts on the Britax Discovery SL? It seems to be more affordable than most other isofix seats. Or indeed most other high boosters full stop. Is this a reason to snap it up eagerly, or to avoid, do you think?

Otherwise I could get the Britax Adventure. (I'm fixating on Britax because we had a britax baby seat - I don't know much about other brands. I have heard of Maxi Cosi, are they better??)

I've only ever had Britax seats too (7 of them! I do have three children though, and bought a big rear facing seat of theirs new for my youngest child as I'd never known how much safer rear facing was when my older two were little).

Anyway, the Discovery SL looks really good, I would definitely buy that one. It's the same shape as the Adventure (which I have two of) so it will fit nicely against your car's seats if they are slightly shaped or 'sculpted'. Both my older two children have slept easily if they've needed to in the Adventures, the headrest is deep and supportive so they've just rested their heads to the side and have never slumped over. Obviously older children don't sleep in the car like babies do, but they've slept when we've set off on holidays in the evening to drive to an airport hotel or a halfway stopover hotel when driving to Cornwall.

I get the impression that Maxi Cosi make decent seats too, and I have seen trained car seat experts recommending the Joie high backed boosters too. They only ones I'd steer well clear of are the Graco high backed boosters. Tests have shown that their back and head sections provide no side impact protection at all!

My niece has the cybex solution q2 and they are really happy with it. I like the look of the britax kid fix 11 xp sict.