Cut bell peppers into large flat pieces, discarding the seeds and membranes. Broil skin side up, until the skin is black. Peel and cut into 1/2 inch squares.
Make a small slit in the skin of the tomatoes, and plunge into boiling water. Dip into cold water then peel away the skin. Cut in half lengthways, seed, and cut into 1/2 inch dices.
Cut the squash into 1/2 cubes. Coat in honey and put into a shallow roasting dish. Roast for 10-15 minutes until golden, then take out to cool.
Peel the grapefruit, making sure to remove all the white pith as well. Cut into 1/2 inch cubes.
Combine the bell pepper, tomatoes, squash, and grapefruit in a glass bolw and gnetly mix together. Chop the herbs and add just before serving. Whisk the oil and vinegar with salt and pepper, and drizzle the salsa on the top.