1. Peel the daikon and chop into a fine mince. Do the same with the onion. Get a piece of parchment on your board, and peel the end of the turmeric. Wash the peeler straight away. Grate the turmeric on the finest grater you have, and wash the grater straight away (or everything will be stained yellow for life!!)
2. Put all the ingredients in a big pot and pour in the vinegar. It should come 3/4 of the way up the ingredients. Then pu in the peppercorns, salt, and sugar. Turn the heat on low and simmer for 30 min, stirring now and then.
3. You are looking for the sauce to have reduced down and become thicker, and all the pieces should be an even tone of yellow and cooked through. Add a splash more vinegar at this stage and whiz half the mixture in the food processor or with the wand.
4. Let it cool completely in the pot and transfer to glass jars. If you're jarring them they will last for years. But like me if you can't be bothered just put it in a jar and eat it up in the next couple weeks! : )