If all else fails you need to coat your throat with something sweet and sticky. Many opera singers use sweet sherry, sipped sparingly, and I know loads of people in the South West who swear by Rum and Shrub. It's an alcoholic cordial you put in with rum and even the strict methodists down there use it for medicinal purposes. Rum and shrub for the throat, Brandy and lovage for the stomach. Try it.