I agree with the prunes, every time he's struggling abit we whack those out and within the next few hours the pipes are cleared again 😅😂 we just get the Aldi one though
Might sound weird but try a potty! My baby was really similar, we often had poonamis in the car seat and once we started solids would go days without going and I saw her straining but often still no poop. Now I put her on the potty when I notice, or 20 mins after a feed if she hasn't been for a day or so and it works almost every time and is so much easier to clean up! If her poos are firmer I give homemade apple puree, always helps 😊
There’s a gap in the market for a car seat shaped potty! We are the same, she goes every time. Waitrose is 5 mins away and we usually factor in a detour there on the way to anywhere. Leave off the vest too until after the change. We usually put in a muslin down in case of any spills, maybe you could get a plastic backed sheet instead if it’s always a poonami. Won’t help the clothes but at least it’ll protect the car seat
My first would do this in her bouncer, which is very similar shape/angle to a car seat, and I assumed it was the angle/position that worked well. She grew out of it eventually (I'm sure by 1), but we joked we should cut a hole in the bottom and add a toilet as she was almost toilet trained already!! Have you got a bouncer you can try? Just pop in and ignore for a few minutes always worked for us! I've seen on other forums people recommending a cloth nappy over the disposable one in the car is helpful to contain the poos!
My little one got constipation while we were away and I fed him the Ella’s kitchen prunes which helped. Not sure what advice to offer beyond that as I’ve not dealt with this issue. The car seat thing could be due to the position she’s in. It can put babies in a position that makes it easier for them to poo, which is why she likely goes when she’s in it. Maybe see if there’s a way to replicate that body position in the house?