Peel and chop nectarine into small chunks. Soak in water and salt for a few hours. I usually leave for about two hours sometimes less and can't tell the difference . Drain and discard water. Combine vinegar and sugar in a pot and slowly bring to the boil, stirring gently. Add all remaining ingredients and turn down to a simmer with lid off. Cook for about an hour until thick. Stir occasionally and keep an eye on it as the bottom can start to burn once it gets thick. If it does start to burn, stir very slowly so the burnt pieces don't mix with the rest. Take off heat and leave to cool. Pour into jars and keep in the fridge