Camper van parked dangerously on a junction and roundabout, does not live in the area

The owner knows someone that lives in the flats and leaves this camper van for weeks at a time. It is a very busy road and is blocking the lane. The person that owns this vehicle comes to check it is still there in another vehicle then leaves again. I believe it is very hazardous to road users as this is the main road in and out of the estate and also a bus route. There is also another large vehicle parked off the road which no longer runs but is just rotting away