In the long debating thread about Dorman Long Tower - I don't want to add to the thread - I think it was Newy who brought up Battersea Power Station as basically having been reconstructed. This is not rare at all. In our area very recently both the Globe and Hippodrome are examples of buildings largely taken apart and reassembled. In fact many of our castles and the great Yorkshire Abbeys were dismantled and rebuilt around strengthening girders after WWII - without a roof the walls of romantic ruins were often standing at perilous angles and totally unsupported. So, up and down the country vast numbers of historic buildings have been conserved by picking them apart and rebuilding them again from their foundations upwards.