Trim any excess fat from the veal and thigh tightly with the aid of a string to hold the shape. Season the meat with salt and pepper and seal in a hot pan with a spoon of olive oil. Remove the meat from the pan and fry the vegetables in the same fat. Add the canned tuna and 2 fillets of anchovies, fry for 1 minute and splash with the wine. Transfer the vegetables with the liquid to a roasting tray, place the meat on top and roast to your liking. When finished cooking, remove meat and allow cooling completely. Put the vegetables in a liquidiser with the obtained juices, squeeze in the lemon and whizz, adding enough mayo to obtain a smooth velvety sauce. To serve, spoon sauce in the centre of a plate and spread it around. Slice the veal into thin slices, and rest on the sauce. Garnish with capers, anchovy fillets, parsley and tuna chunks.