Well - bargain night at Waitrose - Cromer crab for £1 .. so, it would have been rude not to! Mixed crab, chopped celery and tomato in mayonnaise - should have added chopped chili, but didn't have any fresh. Season. Chopped cos lettuce and tossed with good olive oil. Chopped avocado and mixed with lime juice and black pepper. Stack. Victim was very pleased, though said presentation could have been improved by drizzle of lemon oil - and agreed about the chili.