LONDON (Reuters) - A huge find of fossils in Eastern England has revealed a pre-glacial period when the area basked in temperatures now more closely associated with the African savannah, scientists said on Thursday. The bones of seven-ton hippos half as big again as today's descendants have been found alongside those of horses, hyenas, deer, primitive mammoths, rodents and plants giving an unprecedented insight into the distant past. "This is a very significant find," said palaeontologist Simon Parfitt at London's Natural History Museum. "The site is unique in that we have this huge variety of different species all perfectly preserved."...