Grate potatoes and squeeze to remove any excess liquid.
Whisk together the flour, eggs and milk. Add potatoes, fennel and parsley. Season well.
Pre-heat a frying pan and add enough oil to cover the base. Drop 1/4 cup measures of mixture into oil and cook for 4-5 minutes until golden and crisp. Turn over and cook a further 4-5 minutes until golden. Remove to a paper towel lined plate, and keep warm whilst cooking the remainder of the mixture.
For dressing, combine yoghurt, lemon rind and juice, parsley and seasonings. Serve fritters with yoghurt dressing and a crisp green salad.