DIANNE NELMES, 42, has been appointed head of World in Action, Granada's gutsy investigative programme which faces a tough fight for survival in prime time under the new ITV. Ms Nelmes's experience suits the times: she has made successful light entertainment and current affairs programmes. After news editing World in Action in 1984 she left for the BBC as producer of its Brass Tacks current affairs programme. She then launched ITV's This Morning in 1989, which trounced the BBC's rival offering. She was executive producer of entertainment at Granada before leaving for a brief period at Meridian, which won the TVS franchise. World in Action has increased its audience by 45 per cent in three years; the aim is to keep it popular.