Some years ago I sold a radio to a man who told me he had removed all the equipment from Defford where a HIRTA was still shown on the charts. Having reported this to NATS it appeared there was no process for noitifying the removal of such a hazard. In the end, they were looking at pictures of Google Earth to see what was there. West Mercia Police had taken over the site and didn't understand any of the questions relating to high power transmitters. Eventually the HIRTA disappeared.