Van for business and writing off tax

i am thinking of buying a new van for my business,this i beleave can be put against my tax bill..if i have a side window in the sliding door will this make a difference?

A van does not have to have a sliding door. eg a fiesta van is a van!

Once the vehicle is classified as a van, VRT commercial etc., it is allowable without restriction as to value. cars & similar used for business purposes are subject to a value ceiling. Note that the tax write off is 12.5% pa for 8 years. It is not immediate.
Note also that if there is any personal use this must be disallowed from both capital cost and running costs in arriving at tax deduction.