I have the same issue with 3rd to 2nd downshifts. Very distinct clunk, and pretty consistent. May a little more pronounced when the shift happens while braking, versus coasting to a stop. It’s almost as though the control system is giving giving the throttle a slight blip at the same time that 2nd engages. I had the car at the dealer for service and raised this issue with them. The tech took it for a drive and said that it is not normal. He also took one of their demonstrators for a drive to compare. After the service, they said they couldn’t see anything obviously amiss, and would ‘open a ticket’ with Ineos. That was just before thanksgiving, so a month ago, but no feedback as yet. Interestingly if I shift into manual mode and do the 3rd to 2nd shift manually, it’s smooth as silk! All a bit worrying.