Preheat your oven to 220°C (200°C fan-forced). For the vegetable stuffing,heat a large frying pan over medium heat and add the oil. Add the garlic and onion and fry for about 4 minutes until golden brown,then add the remaining ingredients and fry for a further 5 minutes,until softened. Taste and adjust seasoning.
Put the warm stuffing into the chicken,packing it into the back cavity as well as into the neck cavity. Pack any leftover stuffing into a ramekin,or wrap it in foil. Season the chicken well with salt and drizzle with olive oil,rubbing it all over the skin. Place the chicken and any leftover stuffing on a rack in a roasting tray. Roast for 1 hour until the chicken is just cooked through,then set aside to rest while you make the gravy.
For the gravy,place the roasting pan over medium heat and add the butter,flour and Vegemite,mixing until the flour is lightly browned. Add the wine,stirring to lift any brown bits from the bottom of the pan,then gradually add the stock or water,continuing to stir until the gravy thickens. then pass through a sieve. Serve with the chicken,the stuffing and a few salad leaves.