Ds is 9 months(95th centile) and getting big in his car seat, it'll get another couple of months hopefully but nowhere near the 15 months we got with dd3.
This has got us thinking ahead to getting new seats. We currently have TWE (2 between 3 cars) for dd3 who will be approx 3.6 when ds changes up.
We were wondering about changing her to FF at this point (and getting a FF seat while ds uses the TWE ) but I don't know what difference ERF makes at this point. She's a small one and am guesstimating at approx 14kg /1m by then