1. Place a medium-sized pan of salted water on stove top and bring to a boil. Once boiling, add the sweet potato (peeled and cut into 1 cm. dice), simmer for five to seven minutes, then test for doneness - need to be tender but still retain their shape, watch out they don't turn into mush. 2. Drain into a colander and leave to cool down. 3. Take the lemons and, with a small, sharp knife, trim off their tops and tails. Cut down their sides, along their round curves, to remove the skin and white pith. 4. Over a medium bowl - to collect any juice that escapes - remove the individual lemon segments by cutting between the membranes. Put the segments in the bowl; squeeze any remaining juice from the desegmented lemons over the top. 5. Add cooked sweet potatoes to the lemon bowl, then gently stir in the trimmed celery, olives (cut into quarters lengthways), capers, garlic, anchovy (if using), chopped parsley, maple syrup, three tablespoons of olive oil, salt and pepper. 6. The salsa can now be left at room temperature for a couple of hours, or refrigerated and used the next day. 7. To cook cleaned squid (cut into rings, or butterfield and cut into pieces), heat up a ridged griddle pan or a barbecue until really hot - again, this is an essential factor in the cooking process. 8. Throw the squid pieces in the pan a few at a time, without crowding, grill for about one minute each side, then remove, and repeat with the remaining squid. 9. Once all the squid is cooked, toss it gently into the salsa ingredients. The heat of the squid will turn this into a warmish salad. 10. Plate it, dot with the rocket and finish with a trickle of chilli oil.