In a bowl, mix together the chicken and vegetables and pour over the soup. As it's condensed it is very thick and makes a great sauce. I didn't feel that extra seasoning was necessary.
Divide the mixture between ovenproof dishes (or in one big dish if you prefer, in which case, to save washing up, just ditch mixing the filling together in a bowl!)
Lay the pastry over the top and brush with a little beaten egg or milk - if you are cooking straight away.
Cook in a 180-200C oven until piping hot and the pastry is golden.
If you are freezing this, allow to cool and cover before placing in the freezer. Defrost overnight before cooking as above.