Double P11d tax/NIC charge?

Client is a retail shop.  Husband and wife.  Their only vehicle is a shared company van, which is used for both business and private use (not incidental).  The vehicle is used equally by them and they are both named drivers ont the insurance.  Is there anything in the legislation which prevents a double tax/NIC charge?  If not then potentially they both have to complete a P11d and face a BIK of £3,000 on the same vehicle.

Yours responses welcomed.