1. If using the syrup, make that first. Put all the syrup ingredients in a small saucepan and add 400ml of water. Bring slowly to the boil, stirring to dissolve the sugar. Boil rapidly for 1 minute, then remove from the heat and leave to cool and infuse. When cooled to room temperature, pour into a jug, solids and all, and chill in the fridge.
2. To prepare the fruit, halve the papaya, scoop out the seeds, peel and cut the flesh into cubes. Do the same with the guava.
3. To prepare the mango, lay it on its side and make a cut from tip to tip with a sharp knife. Mangoes have a large, solid seed in the middle, so curve your cut to skirt the edge of the seed. Turn the fruit over and do the same on the other side. Slice off any remaining flesh, and discard the long seed. Cut into long finger slices then gently slice away the skin, like you would a soft-skinned avocado.
4. Cut off the top and bottom of the pineapple and cut away the skin, removing as many of the little hard, brown bits as you can. Cut in half lengthways, then in quarters and cut away the core. Chop the remaining flesh into cubes.
5. Peel the lychees, make a slit in the white flesh and remove the centre seed or nut.
6. Gently mix all the fruit in a serving bowl. If using the syrup, strain off the solids and pour over the fruit. Chill in the fridge until ready to serve.
You can serve the salad in a large serving bowl or in individual bowls or glasses. Alternatively, serve the fruit naked with a yogurt dip on the side.