Western Daily Press: Britons have been roofing houses with straw for at least 2,500 years and there are currently about 30,000 homes in the country protected by that most quintessential feature of the countryside — thatch. But the first signs of climate change are now threatening even the thatcher’s ancient art. A succession of weather-ravaged harvests has reduced the supply of suitable wheat, pushing prices up. And experts believe increased humidity and lower sunshine levels are behind the …