Wessex v Bullworker certainly true (believe also written up in Airclues).
Elsewhere new CO at Sennybridge thinks good idea to warn troops about the dangers of the HLS there, so has big wooden sign saying 'Beware Helicopter Downwash' or something similar produced and posted just outside the circle. First Wessex in proves him right - lifted straight up, over and through the blades. Scratch three more blades!