Times: Rodney and Diana Lord are not classic eco-warriors. They live in the middle of a sea of Victorian semis in southeast London. They wear loafers and smartly pressed shirts. And while they know they really should use energy-saving light bulbs, they just "haven’t got around to it". Yet in 2002 the couple became unwitting ecological trendsetters when, on a plot of land in Camberwell, they built a thoroughly modern house with a thoroughly modern roof. The flat roof, covered in …