1.Place choko in large bowl, sprinkle with salt; leave overnight. Rinse choko well under cold water; drain.
2.Combine apple, onion, vinegar, chillies, sultanas, dates and choko in large saucepan; simmer, covered, about 10 minutes or until soft.
3.Add remaining ingredients; simmer, uncovered, about 1½ hours or until thick and rich-brown in colour. Remove bay leaves and chillies; pour into jars, seal while hot.
Store in cool, dark place for about 6 months; refrigerate after opening.