Combine 2 tbs olive oil, parsley, chives and salt and pepper in a small bowl, mix well to combine. Cover and set aside.
Combine the remaining 2 tbs oil, Worcestershire sauce and salt & pepper in a small bowl, mix well to combine. Brush the mixture over both sides of the mushrooms.
Preheat a greased barbecue plate or char-grill on high. Add the mushrooms and tomato slices and cook the mushrooms for 1-2 minutes on each side and the tomato for 1 minute on each side or until just tender.
To serve; place the mushrooms onto the toast, top with tomato and drizzle with herb oil. Serve immediately.