Complex sentence: It was supposed to have been joined with the line from Leatherhead, but due to a centuries old protection order on Ashtead Common to the south or Chessington, these plans were dropped, though in the early 21st Century plans were drawn up for a tunnel.
Split into simpler sentences: It was supposed to have been joined with the line from Leatherhead, but due to a centuries old protection order on Ashtead Common to the south or Chessington, these plans were dropped. In the early 21st Century plans were drawn up for a tunnel.