Yes, she rang them first and they told her to isolate the supply and call an electrician. At that point it wasn't clear what had happened, they could have reasonably just thought it was a faulty light fitting and nothing to do with them. When I realised what the problem was I phoned back but said they wouldn't treat it as an emergency as long as the supply was isolated, and call again in the morning. So no, she had no power overnight which is bad, but she was just relieved to go to bed knowing the light wasn't going to carry on burning!