Hmmm, wonder what would happen in the event of an accident - presumably he has his own insurance for using the company van than, as he's not always using it to do their work, and he's only casually employed by them they wouldn't be paying the insurance would they?
Why would they allow him to use their van if he's not doing any work for them??
All sounds very dodgy to me.
Perhaps you should insist on seeing evidence of him having completed the test... or are they to take the van from him as they aren't offering him any more work until he does so.... :?: