When I went to check the Brio out the safe2go tech looked up the manual, and it doesn't list our model as being suitable. Then we looked at why, and the strap can't fit under the seat runner next to the door cos it's too close to the side of the car, and the design of the seats means it can't be attached at the back of there either.
Okay, so Miss3 is too big for rf. What about options for Miss8mths so she can rear face for as long as poss - assuming that they can be intalled in our car...
You'll find that although the list is helpful - it (like the seat) is for a European market so doesn't take in to account Australian, Japanese vehicles etc etc. So just because it's not on the list, doesn't mean it's not suitable

(Just an FYI for anyone else who reads this).
I don't suppose you can take a picture of the back of your seats can you?
Otherwise, for your 8 month old there's probably only stuff like the Cosco Scenera, Safety1st All In One both of which just use the seatbelt. The First Years True Fit is supposed to be coming on to the market soon though I'm not sure when the ETA is (probably at least a few more months) or the RRP. And the above seats rear-face to 16kg. There is nothing for the 16-25kg child that can rear-face apart from the Zento.
What kind of vehicle do you have?