Mix together 2 tbsps of the oil and 1 tbsp each of the black treacle and marmalade with the salt in a small bowl.
Separate the cocktail sausages and arrange on a lipped non stick baking sheet. If you like you can line it with baking parchment- it might make cleaning the tin easier!
Stir the treacle mixture well and spoon half of it over the sausages. Turn everything together well so that the sausages are lightly coated all over. Drizzle over the remaining tablespoon of oil and stir again.
Put into the oven and cook for 30 minutes, then remove from the oven and put the remaining treacle liquid over. Gently turn again.
Return to the oven and cook for 10 minutes more, or until the sausages are cooked and a deep glistening brown.
Remove the tray from the oven and let it stand for about 5 minutes, then turn once again to coat the sausages in the sticky sauce.