Peel and wash the chosen vegetables and slice or cut them into 1/2 in (1cm) dice according to type. Peel the marrow but leave the skin on the courgettes. Cut the fresh tomatoes into quarters. Rinse and slice any large mushrooms, leave small ones whole. De-rind and chop the bacon.
Heat the oil in a large saucepan over a moderate heat, and fry the sliced onion, chopped garlic and bacon for 4-5 minutes until the onion is softened but not brown, and the bacon is just crisp.
Add the prepared chosen root vegetables (leeks, carrots, potato, celery, turnip, swede and parsnip) and fry for a further 4-5 minutes, turning them over gently in the hot oil. Add the canned tomatoes, pour on the stock and gravy, add the herbs, stir well and bring to the boil, then reduce the heat and simmer with the lid on for 20-30 minutes, until the vegetables are soft.
Add the remaining fresh vegetables (cauliflower florets, courgettes, marrow, tomatoes, mushrooms) and continue to simmer for a further 15 minutes, adding the left-over cooked vegetables for the last 10 minutes of cooking time.
Season well with salt, pepper and a dash of Tabasco. Sprinkle with fresh snipped parsley or chives if available and serve nice and hot.