Wash the fruit, scrubbing the peel, and then cut each fruit in half.
Squeeze the juice from the fruit which can then be refrigerated and used in other recipes.
Now cut each piece of fruit in half again so you are working with a quarter piece.
With a sharp knife, scrape out all the remaining fruit segments, leaving as much of the pith as possible.
Then cut the peel into approximately 0.75 cm (¼ inch) wide pieces and put in a large pan.
Add water to the pan so it just covers the peel and then bring it to a boil. Reduce the heat and simmer for 10 minutes.
Drain as much of the liquid as possible by using a colander and then tip the peel back into the pan.
Repeat the process by just covering the peel with fresh water. Bring the water to a boil and then reduce the heat and simmer for 10 minutes.
Now, drain off the liquid again, but this time reserve 120 ml (4 fl oz) (½ cup).
Put the peel in a bowl and leave on one side.
Now pour the reserved liquid into the pan and add 120 ml (4 fl oz) (½ cup) water.
Take two thirds of the sugar, 190 g (6½ oz) (1 cup), and add it to the pan.
Gently bring the liquid to the boil, stirring to dissolve the sugar.
Once the sugar syrup has come to a boil, pour it over the peel. Cover the bowl and leave to stand overnight.
Next day, transfer the peel, the liquid, and remaining sugar to a pan. Stir over a low heat until the sugar dissolves.
Then bring to the boil. Reduce the heat and simmer for 15 minutes.
Remove from the heat and drain well.
Spread the peel out on two large baking trays/sheets covered with baking paper/parchment. Leave to dry. This can take 24–48 hours. Occasionally move the peel about with a fork to keep the pieces separate.
It can now be stored in the fridge for up to one month or divided into small batches and put in snap lock freezer bags and frozen.