1.Boil, steam or microwave potatoes until tender; combine in a large bowl with lentils, celery and leaves, onion, juice, oil and dill. Season with salt and pepper.
2.Toss fish in combined flour, paprika and salt and pepper; shake away excess flour mixture. Heat oil in a medium frying pan. Cook fish, in batches, until browned on both sides and just cooked through; drain on absorbent paper.
3.Melt butter in a medium saucepan until browned lightly. Add the spinach, cook, stirring, until spinach is wilted; season with salt and pepper.
4.Spoon potato and lentil salad onto serving plates, top with fish and wilted spinach; drizzle salad with a little extra olive oil and serve with lemon wedges, if desired.
Not suitable to freeze or microwave.Note