You are considering writing down the value of the asset.
The guidance at (Work out your writing down allowances
) advises that you can claim 18% tax relief on all ‘plant and machinery’ you buy,
unless the items need to go into: the special rate pool or a single asset pool (for example, because you have chosen to treat them as ‘short life’
assets or you’ve used them outside your business).
Vans fall under plant and machinery.