Roughly chop the sharon fruit. Scrub and coarsely grate the carrots. Chop the celery. Finely chop the ginger. Zest the lime, then slice off the white pith and discard it. Chop the flesh.
Pop everything into a blender. Add a large cupful of ice and 250ml cold water. Whizz till smooth. Add more water to reach your desired consistency.