Place sausages in a hot frying pan with some olive oil-keep turning them.
Now put the kettle on.
After 10 more minutes, test that potatoes are boiled by pushing knife through one-the knife shold go through easily. Drain off water, turn heat right down, mash up adding large knob of butter, a splash of milk and small dollup of mustard and a sprinkle of pepper.
Cut a small amount off the end of one of the sausages to make sure its cooked-it should be grey not pink. Add red onion to pan.
Put boiling water into measuring jug and add instant gravey gradually whilst stirring untill it thickens. Add the slightly cooked red onion to the gravey.
Serve mashed potato in the middle of the plate, with the sausages leaning against it. Pour gravey all over sausage and mash.