Add all the ingredients except the mint to a preserving pan, cover and cook over a gentle heat for 1 hour, stirring from time to time, until softened. Remove the lid and cook for 30–45 minutes until thick, stirring more frequently towards the end of cooking as the chutney thickens. Stir the mint into the chutney.
Ladle into warm, dry jars, filling to the very top and pressing down well. Disperse any air pockets with a skewer or small knife and cover with screw-top lids. Label and leave to mature in a cool, dark place for at least 3 weeks.
To serve, this chutney is delicious as a mezze starter with olives, marinated peppers, yogurt mixed with chopped mint, and griddled pitta bread.