Flew a Bulldog up to Cranwell once and was instructed to park in line with everyone else. Nearby was some grunt Lynx helicopter, rotors running. We parked as intructed and were just climbing out when the stupid grunt idiot lifted into a high hover. The controls thrashed about, the aeroplane threatened to turn over, the passenger nearly fell off the wing - I told him to sit on the wing root. I got back in, switched on the radio and just said to ATC "Get that damn pongo out of here - he's hazarding my aircraft". "He's holding for an ac on 3 mile final" came the reply. "GET HIM OUT OF HERE BEFORE YOU CAUSE AN ACCIDENT!" I politely responded. Fortunately Corporal-of-Horse Dungeater and his horrible clattering contraption then departed....
Too often have we heard of the dangers of light ac and helicopters being operated in close proximity. A helicopter at Kidlington killed a friend of mine when his PA28 was turned over by turbulence - so I don't have much time for people who don't know what their rotorwash does to others.