Coarsely grate the radishes and carrot, then finely slice the shallots and celery.
Mix the white wine vinegar, mayonnaise and yoghurt and season. Then add to the vegetables and combine well until everything is coated.
Notes:
Serve with a salad dish, in a sandwich with cold meat or as an addition to any meal.
If made ahead give a good stir to re-combine all the ingredients before serving.