You can substitute sharp cheddar cheese with any other semi-hard cheese.
If you have gallstones or following gallbladder diet, then substitute sharp cheddar cheese for any low-fat or reduced fat cheese (reduced fat shredded mozzarella is a wonderful choice)
If you can't find self-raising flour, you can easily make it at home.
US measurements: 2 cups all-purpose flour + 3 teaspoons baking powder + ½ teaspoon salt. Metric: 300g all-purpose flour or plain flour + 3 teaspoons baking powder + ½ teaspoon salt