that is very strange. MY husband is carpenter and uses a van. its actually a modified car, ford fiesta, 1.3l and is currently insured with Quinn direct. Its commercial insurance, he has a DOE test every 12 months, instead of NCT every two years, the road tax is cheaper than same size engine if private.
His van is insured 3rd PFT as the first year he was prov ins and only just got licence. now 12 months on passed test and ins is E455. He is 32, but
QUinn Direct were the cheapest quote I could find.
In answer to actual question, you can state van only for personal use, but its still commercial insurance.