Grease well a plain mould or basin. Free the fish from skin and bones, chop the fish finely and rub through a fine sieve. Add to the suet with the breadcrumbs, parsley, salt, pepper and anchovy essence, and mix well. Beat the eggs slightly, add the milk or fishstock and stir into the mixture. Put into the mould or basin, cover with greased paper, and steam gently for nearly 1½ hr.