1.Preheat the oven to 220°C (200°C fan-forced). Combine the port, mustard and 1 tablespoon of the worcestershire sauce in a small bowl; rub all over the beef.
2. Place the beef on a wire rack in a medium, flameproof baking dish. Combine 1/2 cup each (125ml) of the wine and the water; pour into the dish. Roast, uncovered, for 10 minutes.
3.Reduce the oven temperature to 160°C (140°C fan-forced); roast for a further 1 hour for medium or until cooked as desired. Add extra water if the pan juices evaporate.
4.Transfer the beef to a warmed plate; cover to keep warm while making the gravy. Drain the pan juices into a small heatproof bowl.
5.Melt butter in the same flameproof baking dish over a medium heat; add flour. Cook. stirring, until the mixture is well browned. Gradually stir in the remaining wine, then stock, reserved pan juices and remaining worcestershire sauce. Cook, stirring, until the gravy boils and thickens slightly. Strain into a jug to remove any lumps.
6.Serve the beef with the gravy and golden roast potatoes and fresh peas, if desired.
Not suitable to freeze or microwave.Note