Height/ age to stop booster

[Bickles]

DS is 9, 10 in June and he’s 147cm. We have always been very car seat safety conscious and he was RF until nearly 4.
What’s a reasonable height to stop the HBB? He’s looking very tall in it!

By law in the UK it's 135cm or age 12 whichever comes first. It depends where the belt sits on his body and where his legs bend on the seat

I've always been really careful with car seats as well (to the point of being obsessive with it 😳). I read somewhere that seatbelts are designed to fit properly from 150cm. I've used that, in conjunction with the information the pp posted to help me decide when to allow my kids to go without the booster seat.

My DD was fine in some cars before others. Look how he fits into the seat.

150cm - the U.K. limit is very unsafe.