Chop the cranberries in a food processor, or else press them through the fine blade of a mincer, then place them in a saucepan.Now pare off the coloured part of the orange rind with a potato peeler and cut it into very fine shreds. Add these, with the juice of the orange, to the pan followed by the ginger, sugar and spices. Bring everything up to simmering point, stir well, put a lid on the pan and let it all simmer very gently for about 5 minutes.Then remove the pan from the heat, stir in the port and, when it has cooled, pour into a serving dish. Cover with clingfilm and keep in a cool place till needed. Don't forget to remove the cloves and cinnamon before serving!For freezing, when cool transfer the relish to a plastic freezer box and freeze.