Heat oil in saucepan, add in onion and cook until the onion is soft, stirring occasionally. Add curry powder, stirring for one minute.
Add tomatoes. Cook over a medium heat for 10 minutes, stirring occasionally.
Add peaches, sugar and vinegar and cook for another 5 minutes or until peaches are soft but still solid. Put into a good sealing jar and refrigerate to use with your leftover ham.