This salad is about the texture of the pear and not the crunch of the fennel, which is there only for flavour. If nashi pears are not available, use a crisp corella or beurre bosc pear. Lovely, plump organic raisins are sometimes hard to find, so you could substitute Raisins in tea. Pecorino cheese, instead of the parmesan, would be a nice twist with its salty flavour, but something creamy like mozzarella or burrata would make this salad a much heartier meal.