Roast guinea fowl with chestnut, sage & lemon stuffing

INGREDIENTS

• 1 small guinea fowl , about 1kg
• 8 rashers streaky bacon
• 50g soft butter
• 1 onion , unpeeled and thickly sliced
• 2 tbsp plain flour
• 350ml strong chicken stock
• cranberry sauce, roast potatoes and vegetables , to serve
• 1 onion , chopped
• 25g butter
• 1 tbsp chopped sage
• 50g walnuts , finely chopped
• 50g breadcrumbs
• zest 2 lemons
• ¼ tsp ground mace
• 100g cooked chestnuts , quartered
• 1 medium egg , beaten with a fork