If the driver parks outside your house and blocks access to and from your driveway, you can report it to the police and they do have powers to ticket the vehicle. However, if he isn't blocking your driveway, there's nowt you can do (as long as the vehicle is taxed, insured and has a valid MOT certificate (if necessary) ).
it is NOT illegal to block an empty drive, check it out with your local plod, it is illegal to block a vehicle in a drive (in case it is required to be used in an emergency), but if you return to find your drive blocked and you cant park nothing will be done,
to the OP get a life FFS, and to those who advise calling the company etc, NO, what if the driver gets pulled as a neighbour has complained and told he cant take the van home, he cant get to work on time and loses his job, it is snobbery to complain about works vans, it gets on my wick, i live 100m from a train station and often come home to find cars parked there, so what as long as they are legal they can park where the like, ok it is cars but if my next door neighbour got a job which supplied a van to add to his and her cars then good for him, i have had works vans home for years and have taken up parking spaces so if it is all right for us it is all right for them as well, live and let live and if anyone needs a real problem to take up their time, ask around plenty of folk have enough to share round