Really? My 136cm 6 year old still sits in one with room to spare. My 140cm 8 year old can also still fit. DD3 is in a hybrid infa seat/booster. She is still in 5 pt harness mode and DD1 mentioned the other days that her (DD1's) shoulders are just over the top marker (when she was macking around sitting in it) that means you are too big for the seat.
Yes, really. She was looking very uncomfortable and scrunched up in it so that's why we took her out of it. We are still investigating putting it back in but if she doesn't fit in it properly, I don't feel like it's safe anyway.