Non resident cars obscuring entrance to resident car park

Entrance to resident car park is being obscured by non-residents cars parked dangerously close to the exit. Vision of incoming traffic is impaired, and making a left turn out of the carpark is therefor tricky. Ideally, some yellow lines are required here in order to keep the exit clear. In the above photo, I have parked my black Audi in the offending spot (but far enough out of the way of the exit to be safe) to block members of the public doing the same. Quite often, cars will be parked right of the end of the yellow markers I have added to the photo.