Shred or dice the cooked chicken into small pieces and place in a large mixing bowl.
In a separate bowl, whisk together the mayonnaise, mild curry powder, mango chutney and fresh lemon juice until smooth and golden. Season with salt and freshly ground black pepper to taste.
Add the sultanas and flaked almonds (and, if using, the finely sliced spring onions and chopped fresh coriander) to the chicken.
Pour the curry mayonnaise sauce over the chicken mixture and gently fold until all pieces are evenly coated.
Cover the bowl and chill in the refrigerator for at least 30 minutes to allow flavours to meld.
Serve piled into sandwiches, with a green salad, in jacket potatoes or as part of a buffet spread.