To make the dressing, bring a small pot of water to the boil and place eggs into boiling water. Allow to boil for 8 minutes to make hard-boiled (but not rock-hard) eggs. Plunge into cold water, sit for 5 minutes, then peel and roughly chop.
Gently mix eggs with mayonnaise and vinegar. Taste for seasoning and set aside.
Boil potatoes in plenty of salted water for 15 minutes. Drain then press to a rough crumb with a fork.
Toast the bread, rub with the whole garlic clove, then blitz to a chunky crumb with half the parsley. Heat a frypan and toss the crumb with a tablespoon of oil and some salt to toast a little further. Tip out and reserve, wipe the pan and return to high heat.
Dry calamari really well then toss with a tablespoon of oil and add to the hot pan. Cook for 1 minute before adding the sliced garlic and dried chilli. Fry for 2 minutes then add the warm potato, the radicchio, the rest of the parsley and the fennel. Pour over the remaining olive oil and the lemon juice, add the breadcrumb mixture and gently mix together.