Could be a combination of people putting new car buying on hold and folk cancelling orders.
I know from the none Motability car forum I participate in that those who ordered over a year ago are sticking to their orders because they have become such great deals being there has been a few price rises since they ordered and the manufacture has a price guarantee.
At the time of there orders the manufactures were giving poor discounts but now there giving even less, that, and along with the increases in interest rates those orders have equality built in to them now something I can’t imagine ever happening before.