Not worth going into a van or double-cab now unless you have a way to get out in a little over a year - and that is expensive whether you buy or lease the vehicle thanks to first-year depreciation.
The BIK rules are changing for people in commercial vehicles. From April next year, if you have any private use you pay tax on a benefit of £3000 per annum. For most, you are then better off in a CO2 efficient car.