As far as I know, Black Romany wasn’t published separately, but appeared in:
Black Beauty’s Family, Hodder & Stoughton, 1978
Black Beauty’s Family, Chancellor 1996
Reprinted in More From Black Beauty’s Family, Red Fox 2001
Black Romany is an ancestor of Black Beauty: an early Victorian horse. Romany has an epic journey across country, and experiences a visit from Prince Albert and Queen Victoria before settling down as a much loved hunter.