Slice bread in half, across the middle. Layer the meats and cheeses on to the bottom half of the bread. Add some chopped piccalilli and olive mixture. Top with the pickled onions, drizzle with olive oil and red wine vinegar, and add the radish sprouts.
Cut into large sandwiches and serve.
Prepare vegetables, add 1/2-cup salt, and allow to sit overnight in the refrigerator. Drain vegetables and place in heatproof bowl. Place remaining ingredients in saucepan and heat to boil. Pour over vegetables and allow to cool. Refrigerate and serve as needed, keeps for about 2 weeks.