When Margaret Thatcher unexpectedly emerged to challenge Edward Heath for the Conservative leadership in 1975, the public knew her only as the archetypal Home Counties Tory Lady, more famous for her hats than for any outstanding talent.Yes almost overnight she reinvented herself.Journalists who set out to discover where she came from were amazed to find that she had grown up above a grocer's shop in Grantham.Within weeks of her becoming Tory leader an entirely new image was in place, based around the now famous corner shop beside the Great North Road; the strict Methodist upbringing; and her father, who taught her the 'Victorian values' which were the foundations of her subsequent career.