I can’t see this coming in, though we never know, but if you walk into a dealership as a private customer today and ordered a car the order price is set and guaranteed by the manufacture, well it was years ago when I last brought a new one privately.
Only the other day I read about someone with a private buy ordered a car at £39,800 and the price was fixed but in the time between the order and the delivery the cars price had increased to to over £40k making the buyer liable for the extra tax that that bring with it with no escape from paying the tax.