I assume everyone knows how to make mashed potatoes and how to fry a sausage so the recipe will only deal with making the red wine gravy. To make a full meal I'd suggest serving with the sugar roasted alliums from the previous post.
1/2 pint of red wine
1/2 pint of vegetable stock
1/4 pint Balsamic vinegar
2 tsps plain flour
Put the red wine and stock in a pan and simmer to reduce the volume by half (to 1/2 a pint). Mix the plain flour into a paste with 2 tbsps of cold water. Add the balsamic vinegar and flour paste to the pan. Whisk vigorously until the sauce thickens.
Note: This amount of sauce is usually way more than we need for a single meal, however, it freezes really well. I usually freeze it in ice cube bags and then defrost and reheat as much as I need at a later date.