Scrub the potatoes and slice in half. Pop them in a pan and cover with cold water. Add a good pinch of salt, cover and bring to the boil, then reduce to a simmer for 10 mins, or till tender.
Trim the French beans. When the potatoes are nearly done, add the French beans to the water. Simmer for a further 2 mins, then drain well and transfer to a large bowl.
Add half the ricotta to a small bowl. Pick half of the basil leaves. Roughly shred them and add to the cheese. Grate in the lemon zest and sprinkle in a little salt and pepper. Stir well to combine.
Peel and grate the garlic into a separate bowl. Squeeze in the lemon juice. Whisk in 2 tbsp oil and a good pinch of salt and pepper. Pour the dressing over the potatoes and beans. Toss together well.
Trim the courgette and use a vegetable peeler to turn it into ribbons. Rinse the radishes and leaves and shake dry. Finely slice the radishes and their leaves. Peel and finely slice the red onion. Add them all to the bowl with the potatoes and beans.
Spoon the salad onto plates and top with dollops of ricotta. Finish with the remaining basil leaves.