Torr Waterfield explain why it's not important whether the vehicle is a van. What's important is that it's not a car.
For VAT purposes it will be a car if:
It is of a kind normally used on public roads, has three or more wheels and either:
Vehicles capable of accommodating only one person;
Vehicles with a gross weight of at least three tonnes;
Vehicles with a payload of at least one tonne;
Minibuses (for 12 or more people);
Ambulances, prison vans and other special purpose vehicles.
For P11D/capital allowances purposes it will be a car if:
It is a mechanically propelled road vehicle, which is not:
a goods vehicle (of a construction primarily suited to the conveyance of goods or burden of any description);
a motorcycle (fewer than four wheels and an unladen weight of no more than 425Kg);
an invalid carriage (specifically designed for disabled use and an unladen weight of no more than 254Kg); or
a vehicle of a type not commonly used as a private vehicle and unsuitable for such use.
People (at least living ones) aren't goods or a ‘burden of any description’, so anything with seats in the back (other than a double cab pick-up type vehicle with a one tonne+ payload) is likely to be regarded as a car for direct tax purposes.
Anything with seats in the back and/or roofed and windowed accommodation behind the driver (other than a double cab pickup with a one tonne+ payload) is likely to also be a car for VAT purposes.
For clarification use the link below.