Put a large pan of water onto the heat and bring to the boil, add a pinch of salt then add the pasta and cook according to the instructions on the package, making sure not to over cook it. Now heat some olive oil in a large saucepan.
Add the leeks and crushed garlic and allow to wilt down, don't let the garlic burn, it will make the dish bitter so stir whilst they cook. Add the red pepper, two thirds of the chopped tomatoes, tomato purée, a pinch of salt, white wine and celery. Cook the sauce till it starts to reduce, do not allow the sauce to boil rapidly as you want the seafood soft and succulent.
Take your firm white fish and cut it into bite-size chunks, remember that fish shrinks when cooked so chop the chunks slightly bigger than you want to end up with. Add the firm white fish to the sauce along with the squid heads and calamari rings.
Once the seafood has turned opaque, add the clams and mussels, make sure you discard any that don't open once they are cooked. Once all the seafood is cooked add the capers, lemon zest and parsley, carefully stir using the handle of a wooden spoon so you don't break up the chunks of fish.
Add the remaining tomatoes at the end for a really fresh flavour, along with the basil, cooked prawns and chives. Strain the pasta and put it on a large plate, then coat with the sauce, allow all the juices to soak into the pasta.