Does anyone know of a car insurance company which offers insurance to people who do not own their own car but drive vehicles at work? So far I have had very little success in tracking one down.
You can only insure something if you have a financial / insurable interest in what you want to insure.
As the vehicle belongs to your company (I assume this is the case) then they should insure the vehicle, in their company name and either name the drivers who will be driving it, or insure it on an 'any driver' basis.
I don't think you will find an insurer in the land who will insure the vehicle as your company are asking, as it is completely incorrect.