Mix all the ingredients thoroughly in a large bowl and leave aside for about an hour, preferable overnight, for the flavours to develop.
Soak the sausage casing in warm water for 20 minutes, then lightly pat dry with a kitchen towel.
Snip the end of a piping bag, about an inch from the end.
To make the sausages, slip the casing over the cut end of the piping bag and keep pulling the casing over as much as you can, gathering it back, concertina style.
Leave about 6 inches of the casing hanging, to allow you to tie it up at the end.
Start filling the casing with the sausage meat.
Keep filling, topping up the piping bag as you go along.
When done, cut of the extra casing and tie one end.
Start to twist the sausages into links about 5 inches (12.5cm) long, making 3 twists at each intersection. Make clockwise twists the first time, the second link should be anticlockwise, the third link clockwise, and so on.
Let the sausages sit in the fridge for an hour, to settle.
They'll keep in the fridge, covered, for 2 days or freeze for up to a month.
Cook as you would regular sausages - on the stove, under the grill, on the barbecue, etc.