We had all our vans insured through CVD, got a renewal quote at the beginning of the month for the main window cleaning van, increased premium by 50%, when I phoned them up it was the best deal they could find as I have an "any driver over 25" policy.
I went onto the net and had a look for myself, got a quote through Autotrader from More Th>n for less than I paid last year, they then phoned me the next day and asked if they could take some more details to see if it could be reduced any further, saved another £150 on their original quote.
It's always worth shopping around, these companies make their money from people just renewing without asking.