I helped a friend of mine place her order for a new Motability car a few months ago. She was asked if she wanted to pay the advanced payment up front “as it would expedite the paperwork when the car was ready for collection”.
I told the salesman that it wasn’t Motability policy and that my friend would only make the AP when the car was ready for collection and the specification was verified as being exactly what she had ordered. I pointed out to him that I was aware that due to the shortage of chips and other technical parts, cars were being built with missing equipment and advertised features and he reluctantly agreed that this may be the case at the moment.
A short while later the AP for her car dropped by £700 to only £99 AP. I went with her to the showroom immediately and asked them to cancel her order, and reorder the same day at the £99 AP. This was done and a copy of the order was emailed to me on her behalf that afternoon. If she had paid the £799 on the day she placed her order it may well have made the dealer more reluctant to cancel and reorder.
This is just one reason not to be talked into paying the AP in advance.