Whisk together the grapefruit zest
and juice, oil, vinegar, sugar and dill
to make a dressing. Mix half with the
prawns and allow to marinate for 10 mins.
Just before serving, gently toss the
cucumber, shallots, frisée and rocket
with the remaining dressing. Add a pile
to each of 6 starter plates, along with the
prawns and grapefruit segments. Scatter
over the pomegranate seeds and serve.