Put the shallots into a bowl with the apple cider vinegar and set aside.
Roast the fennel seeds, cinnamon and anise seeds in a hot dry pan. Except for the peaches, mint and shallots in vinegar, put all the ingredients into a large pan. Simmer on a low heat for 10 minutes, then set aside and leave to cool.
Add the peaches, mint and shallots in vinegar to the pan and stir gently.