Thread the beef onto 8 skewers together with the shallots, courgettes and red peppers. Season with salt, black pepper, oil and balsamic or wine vinegar.
Combine the tomato ketchup, Worcestershire sauce and Tabasco with the shallots, tarragon, oil and wine vinegar. Season to taste and set aside.
Cook the kebabs on a barbecue if possible. If not, griddle the kebabs over a hot heat for 3-6 minutes on each side.
Serve along with the dressing and warm baby new potatoes.