Cut the peaches in half, remove their stones and then cut each half into 6 segments. Add to a large bowl.
Hull the strawberries and cut into quarters. Add to the bowl with the peaches.
Cut the grapes in half and add to the bowl of fruit. Add the blueberries, then the vinegar. Gently toss together, cover and leave to sit for 10 minutes.
When ready to serve, dish into bowls and scatter over the mint.