21mo is undoing the straps (tried anti escape system but she has got out of that) and is now also undoing the buckle on her carseat.Today she was standing up in her carseat whilst I was going around a roundabout, trying to find somewhere safe to stop.
Wary of chest clips due to safety concerns but probably would have tried it if it was just straps not the buckle as it would have been less dangerous than her climbing about, and I think now she can do the buckle she will open the chest clip too anyway, plus whenever the buckle isn't on i would still need to stop and intervene to do it back up.
Have tried distraction with screens/food/music/toys etc but she is still doing it.
Only thing we can think of now is covering the buckle with something, but don't want to make it hard to get her out in a hurry, or do something which means the crotch buckle isn't snug to her body.
Any tips from anyone who has been through similar much appreciated!