Dry fry the cumin seeds in the base of a preserving pan, stirring constantly for about a minute until golden.
Add the vinegar and water plus all the other ingredients except the lime juice and zest.
Cook over a low heat, stirring, to dissolve the sugar.
Bring slowly to the boil.
Lower heat to a simmer, keep stirring, (you don't want it to stick) and cook for 45 minutes or until there's just a single layer of liquid on the surface.
Add lime juice and zest and simmer, still stirring, for another 5 minutes.
Ladle into hot sterilized jars and seal immediately, labelling when cool. (I used 3 x 500 ml jars with a little spare).
Store in a cool, dark place for 6 – 8 weeks before using.
Refrigerate after opening.