There is no VAT on used car sales, b.
The dealer pays VT on his margin, but he doesn't charge you VAT, what with the VAT having been initially paid when the car was sold new.
Of course, if a new car is pre-registered by a dealership as a demonstrator and the VAT reclaimed, when the vehicle is subsequently sold as a used car, VAT will have to be added back into the price. Such a car is said to be 'VAT qualifying'.