Steve we have 5 vans insured on a multi van insurance with More Than, they beat Commercial Vehicle Direct by a mile.
Most insurers will be able to offer a multi vehicle policy.
With Multi vehicle policies each vehicle continues to accrue it's own NCD, whereas with Fleet insurance there is no NCD but you pay reduced fees depending upon your claims over the previous 3 years.
In August we are probably going to convert to a fleet insurance policy (min 5 vehicles) but I haven't been given a final cost yet.