I'm not sure what will be tax deductable . My last van was taken into account in my tax return and realy I'm just replacing it with the insurers cash so I wouldn't think so
from last time i bought a new van 60% of the value the first year and 25% of what's ever left every year after that if you borrow the money you can claim the interest as well + insurance +road tax +fuel +AA/RAC etc cover + repairs (it is a new one after all)