Remove any discoloured outer leaves and cut the cabbage in quarters. Remove the hard white core, shred the cabbage finely and put it, in layers, into one or two large bowls, sprinkling each layer with salt. Cover and leave for 24 hours.
Meanwhile, put the malt vinegar in a stainless-steel or enamel saucepan and add the cinnamon sticks, allspice berries, cloves, mace and peppercorns. Bring to the boil, then remove the pan from the heat, cover and leave until cold. Strain the cold vinegar through a muslin-lined sieve into a jug or bowl and discard the spices. Cover the bowl and reserve until needed.
Next day, transfer the cabbage to a colander and rinse under cold running water. Drain on several layers of paper towels, then pack loosely in clean jars. Pour the cold vinegar into the jars to come at least 2 cm above the cabbage. Cover with vinegarproof lids, label and date, and store in a cool, dark cupboard. Let it mature for one week before using, but use within two months as pickled cabbage loses its crispness after this time.