Bangers & mash with onion gravy and mushy peas

Ingredients

• 4 english style pork sausages
• 1 12 oz bottle of beer
• 1/4 cup chicken or beef stock
• 1/4 cup white wine
• 1 tablespoon flour
• 2 slices of bacon
• 1 yellow onion
• 2 cloves garlic
• 1/4 teaspoon dry sage
• ground black pepper
• kosher salt
• 1 pound potatoes
• 1 tablespoon butter
• 2 tablespoons milk
• 1 cup frozen peas
• 1 tablespoons butter
• 1 teaspoon olive oil
• 2 green onions