In similar vein, I'm aware that publishers like to know that their authors have several ideas rather than just one. So, although I believe Journeys from Wimbledon Common will have a wide appeal, I've been considering ideas for a second book.
After extensive brainstorming, consultation etc, the following items have come up as having perennial appeal to a wide range of readers:
So that seems simple enough. It only remains for me to write Vampire Penguins versus the Nazis - a comedy thriller set in Latin America, involving a deadly battle for possession of priceless dinosaur remains. It can't fail to be an international bestseller.