Scrub the oranges, cut them in halves, squeeze out the juice and remove the pips. Cut the peel into strips and chop.
Place the chopped oranges, juice and water in a large saucepan; bring to the boil and simmer for 2 hours, stirring occasionally. Make sure all of the added water is evaporated off.
Add the Sure-Set, stir over a low heat until it is dissolved then add the whiskey bring to the boil and boil vigorously for 4 minutes. (See 'Adding Sure-Set' for details on boiling and timing).
Allow to stand for about 5 minutes, stirring occasionally to distribute the peel.
Pot and cover in the usual way; label and date. (See 'Potting and covering' for details).