Convert from firkin [butter, soap] to quarter [UK]

Unit Definition (firkin [butter, soap])
The firkin [butter, soap] is a traditional unit of weight for butter and soap, equal to 4 stone or 56 pounds (about 25.40 kilograms).

Unit Definition (quarter [UK])
The quarter [UK] is a traditional unit of weight equal to 1/4 hundredweight. In Britain, one quarter equals 28 pounds (12.7006 kilograms).