I am aged 88, and during the 30's my father worked in a lairage(abattoir) and part of his wages was the offal.Amongst the items he regularly brought home were, Sheeps heads, sweet breads, chicklings, lambs frys, ox liver, ox hearts, lambs hearts. Other offal like tripe and hodge were available, plus brawn and black puddings. All of which are extremely tasty when cooked properly. My mother was a cook. For the past 8 years I have visited Calis I always have a couple of liver and onions, in different restaurants, and have always found them delicious.