The best cottage pie with ale gravy

potato 41.0% , beef 28.0% , ruddles best ale 14.7% , Taw Valley ® Mature Cheddar cheese 7.8% , onion 4.2% , Henderson's relish 2.1% , carrot 1.1% , butter 0.5% , wheat flour 0.3% , celery 0.1% , corn flour 0.1% , yeast extract 0.0% , Šalt 0.0% , rapeseed oil 0.0% , thyme 0.0% , beef extract 0.0% , tomato purée 0.0% , Colour 0.0% , spice 0.0% , yeast 0.0% , sugar 0.0% , beef fat 0.0% , onion 0.0% , sunflower oil 0.0%