Chop the onion and bacon in small pieces, put in a heavy pan, and cook gently until the fat runs from the bacon, and the onion and bacon are soft and golden. Add the mince and cook until mince browns. Stir in flour mixed with a little water, and the rest of the water, herbs and seasonings, and cook until mixture is thick and well blended. Roll pastry into two rounds and line an eight-inch pie plate with one. Put in filling, and cover with second round of pastry. Bake at 400°F, 200°C, gas mark 6 for thirty minutes.