Set oven to 200°F (93 °C)
Put all of the ingredients except the port in a large ovenproof bowl or casserole and mix together well.
Cover tightly with tin foil or a lid and place in the oven. Leave to warm in the oven for 90 minutes.
Remove from the oven and allow to cool.
Add the port and stir really well.
Transfer the mixture into clean jars. Be sure to sterilize them if you will be storing for an extended period. See recipe notes below for how to sterilize.
