Beans with marrow and corn

A very simple dish, based on a latin american one.  You can use any white beans; I use black eyed beans.  We have so many courgettes in the garden at the moment so a few have turned into marrows, but pumpkin would work just as well for those in colder climes!  To me this is a great comfort food.
3 tbsp olive oil
1 large onion peeled and chopped
1 large clove of garlic, crushed
1 can of tomatoes
fresh basil
fresh oregano
225g black eyed beans-soaled and cooked until very tender
1 marrow cut into largish dice
1 sweetcorn-cooked and kernals cut off
sea salt and black pepper

Heat the oil in a good sized saucepan and fry the onion for 5 mins, or until beginning to soften, then add the garlic, tomatoes (if using dried herbs add now) and cook fairly fast for about 10 minutes, without a lid on the saucepan, to make a thickish sauce.  Stir in the dried drained beans and marrow and simmer gently for about 10 minutes, until the marrow is nearly cooked, then mix in the sweetcorn and continue to cook until everything is tender and the mixture piping hot.  Season with salt, pepper and the fresh herbs and serve!