We have made the call that Nathaniel can now officially sit. He is really quite stable and can lean over and pick up things without over balancing. We were going to take a photo to show off his skills, but he immediately decided that he would rather stand.
He has realised that in order to stand, you have to straighten your legs, but isn't quite sure how to get into an upright position. This means that he spends a lot of time lying down, having straightened his legs from a sitting position.
This is a cheating photo - he's not really sitting unaided. You'll just have to believe us that he can!