Through work I met a researcher that has worked in the area of child sex abuse within organisations and they said the first people the abuser grooms are the people in control, the people with power to stop it. They cultivate relationships with them, warn them of the duplicitious nature of children & that they make things up for attention, so that when a child eventually complains the person in authority is faced with a 'he said she said' situation in which one of the parties is someone they like & respect and the complainent is a disgruntled child making a scene that they'd already been warned to expect.
Saville was like that but on steroids. He had a very high public profile was photographed with the PM, the Prince of Wales, Chief Constables, the head of the hospitals. If he turns up asking for the keys to the morgue, saying 'the bossman said it is ok', it would be very hard for a lowly member of staff to decline whatever misgivings they had.