There are many seven or eight-seater cars on the market today that you would presume you would be able to fit five child seats in, but as I have found in my testing this is not the case! Either the second row doesn't fit three child seats or the rear row doesn't have top tether points, or you can't access them without uninstalling the second-row child seats!!
Here is a list of all the seven and eight-seater SUV's, that I have reviewed so far, and found would fit four or more child seats in the back:
The Mazda CX-8 has FIVE top tether points?!! FANTASTIC!! They are all within plastic guides on the seat backs, apart from the central one in the second row which is right underneath the seat and I found I required an extension strap for the child seat. There are ISOfix points in the two outer second-row seats only and I found there was enough room for me to install three big child seats across the second row while using the ISOfix because there is plenty of space across the second-row seats, which is unusual and great! In the third row, I installed two big Britax child seats using the seat belts and top tethers, and there was ample room for them. The second row slides to adjust leg room and we found you could have a 184cm passenger sit in front and behind a rear-facing infant capsule. In both positions, there was 25cm of knee room which was impressive! The headroom in the third row was better than in the VW Tiguan Allspace but still only enough for the 184cm passenger to last a 30-minute journey before they wanted more space! For accessing the third row, the second-row seats slide forward and small kids could perhaps climb through but an adult could not reach through the gap to fasten buckles or bigger kids climb through without removing child seats. The second-row seatbacks are split 60:40 and the 60% is on the kerb side so you actually have to remove two child seats to access the third row from the kerb side of the car which seems biased to left-hand drive countries. I found that the third-row seats are very comfortable to sit in and I'm 162cm.
The Mazda CX-9 has FIVE top tether points?!! Yes! They are in all three central row seats and both third-row seats too! But the central seat's anchor point was strangely located slightly under the seat base and not clearly labelled, which didn't fill me with confidence when I was installing my child seat! There are ISOFix points in both the outer second-row seats, they are hidden in slits of the seat leather so you do have to line them up carefully and are not as simple as when they're within plastic guides. The second-row seat, behind the front passengers, has a folding mechanism that allows it to fold and move forward with a child seat installed (if using the ISO Fix, not the seatbelt) and gives a big step-through access to the third-row seats! I managed to very comfortably fit five large Britax child seats into the CX-9, still with plenty of legroom in the front for driver and 23cm of knee room for the front passenger! First, I put the Britax Platinum Pro in the third row and the rear-facing Britax Unity infant capsule and Britax Graphene (installed as rear facing) in the second-row outer seats and the Britax Kid Guard Pro booster seat in the central seat, there was plenty of space around the seats and installation was really simple.
When it came to the installing child seats in the Carnival, it took a while to get to grips with all the different seat combinations, sliding mechanism options and top tether and ISO Fix positions! There are four top tethers in total and three ISO Fix. The second-row seats are made up of three individual seats that slide and fold up separately. The two outer seats have ISO Fix and top tethers, the ISO Fix are not within plastic guides, they are between the seat back and base and I found them relatively easy to connect to them. The top tethers are really far down on the seat backs, I found for both rear facing child seats I tried to instal there I needed an extension strap. In the second row, I installed the rear-facing Britax Platinum Pro and Britax Graphene child seats in the two outer seats and I was able to sit in the central seat between them. In the third row, there are three seats too, they are split 60:40 and there is ISO Fix in the seat on the 40 split and top tether in that seat back as well as top tether in the central seat. I was a little confused by there being top tethers in the two seats next to each other and not in the two outer rear seats. Again the top tether anchor points are really far down on the seat backs, I didn't need an extension strap with my forward-facing child seats, but would with rear facing. I was able to install two forward-facing child seats in the third row of the Carnival, the Britax Maxi Guard and Kid Guard Pro fitted next to each other and I could just squeeze into the seat beside them! Head and legroom are excellent in the third row. Although I could only get four child seats into the Carnival because there are only four top tether anchor points, the good thing about it is the remaining two seats are usable by adults! So the Carnival is good for a growing family where some kids are too big for child seats and will be just on the car seats. Legroom was excellent! With child seats in both rows, there was plenty of legroom for each row and the front passenger and driver. To climb into the central seat in the second row there was enough room when the second-row seats are slid back to climb around the front of an installed child seat.
I was able to install four child seats in the Honda Odyssey which was great. There are top tether anchor points right at the bottom of both second-row seat backs, I found I needed an extension strap for the rear-facing child seat. There is ISOFix in the two second-row seats, there were two top tether anchor points for the outer seats in the third-row model I tested, but no ISOFix. The top tethers were not on the seat backs but on the lip of the boot opening, which caused the tether straps to go across the boot space which is not a practical design at all. I managed to install two big child seats in the back there, I did struggle a little to post them in and out through the doors and folded forward seats though.
I did manage to install four child seats in the Lexus RX350L there were limitations and I found it is not the most practical or family-friendly car! The large boot of the Lexus RX350L takes away from the space inside the car and when I came to install child seats, I discovered there is not really enough legroom in the car for it to be used as a genuine seven-seater. There are three top tethers across each of the backrests in the second row of seats and one in the third row of seats, in the backrest on the passenger side. They are all well labelled and easy to access and connect to. In the second row, there are ISOFix points in the two outer seats and although they are not within plastic guides, they contrast to the seat upholstery so are easy to locate and connect. I found I could not fit three forward-facing child seats across the second row there was not enough shoulder room, I could fit a forward facing Maxi Guard Pro booster seat in the central seat and a rear-facing Britax Unity infant capsule on one side and Britax Graphene (rear-facing) on the other outer seat. In the third row, I installed the forward facing Platinum Pro child seat, using the seatbelt and top tether, but there was very little leg room. I found the only way to access the third row was bringing the second-row seatback forward and so having to uninstall any child seats in the second-row outer seat! Which is totally impractical! Also with child seats installed in the second row, there really wasn't any legroom in the first and third rows!
I could install four large Britax child seats into the Infiniti QX80 and there was so much space in the second-row seats that I could use the ISOFix rather than the seatbelts to connect the two outer child seats! I fitted the Britax Platinum Pro forward-facing and Britax Graphene rear-facing in the two outer seats and the Britax Kid Guard Pro booster in between. In the third row, I fitted the Britax Maxi Guard Pro using the seatbelt and top tether. In the Infiniti QX80, the only way to access the third row was by folding forward the second-row outer seat so you would have to uninstall any child seat fitted there! Which is totally impractical! It's also disappointing in a seven-seater car!
In the Nissan Pathfinder there are two ISOFix points, one in each of the outer second-row seats. There are four top tether anchor points, in the backrests of all three second-row seats and there is one in the right-hand third-row seat! This was fantastic and allowed me to install four child seats using the seat belts and top tether points. In the third row, I installed the Britax Maxi Guard Pro forward facing booster seat. The seats were relatively easy to install and the only thing I had problems with was getting the top tether strap through the central seat headrest bars, as they were too close together making it very difficult. There was good space for forward-facing and rear facing seats across the second-row. I installed the Britax Unity infant capsule rear facing on one side, the Britax Graphene forward facing in the middle seat and the Britax Platinum Pro would fit forward or rear facing in the other outside seat. Legroom was also very good in the Pathfinder. The second-row seats are split 60:40 and both sides slide to adjust the legroom. I found I could sit in the third row comfortably with a rear facing child seat in the second row (and the second-row seat in the furthest back position) and the driver's seat has plenty of room for most size drivers. The second-row seats also have a mechanism that allows you to move an outer seat forward with a child seat installed and have enough room to climb through to the third-row seats. The child seat MUST be using the ISO Fix and top tether connectors though, not the seatbelt and top tether.