did fit 3 car seats in the back (the ones we had at the time). However, so did our honda jazz!! This car is very small on the oustide, but a bit like a tardis. Also, the rear seat is one flat bench (not fancy moulded seats that can make fitting seats more difficult). I do suspect the inside of the door was much more "space saving" than on the omega. I was very surprised this fitted when we tried. We now have a zafira, not bad and may fit 3 car seats in the back, depending on the seats. Make sure you dont squeeze in too many seats and get one seat potentially interfering with the buckle on the one next to it. Yes, clueless. By your own admission you seem to have the vast experience of 2 car seats presumably chosen without first trying them together in your car to go on. Me calling you clueless is no more "abrasive" or "not nice" than you calling me wrong, the difference here is I'm right. of course I'm not going to list every car seat I have ever used and every combination that works (it's a lot) and even if I owned a camera I wouildn't be running around taking pics to satisfy your need for proof. Go to any store that has a wide range of baby/child car seats and boosters and you will see they are not all the same size or shape. if you want 3