Hmm. Yet again this week not the reverse you were imagining? Yes, once again, this one is the overseas version of another set.
So let us start our journey with RB.21, the British American Tobacco Booklet. This tells us it was issued in 1926, in Malaya. That leads us to a section called "Ogdens Additions and Corrections", where it is described as :
215.71 DERBY ENTRANTS, 1926. This series was issued as follows :-
A. Ogden`s Home issue - titled "Derby Entrants, 1926"
B. Anonymous issue, with letterpress on back - titled "Famous Racehorses".
And this is indeed correct, it is an addition, for the Ogdens reference book simply lists that set, or rather that group of sets, as:
125. DERBY ENTRANTS. Fronts printed by letterpress. Backs in grey with descriptive text. Home issues in years stated.
71. 1926. Series of 25. Fronts in colour. Horses and owners` colours.
72. 1928. Series of 50. Fronts in colour. Horses only.
73. 1929. Series of 50. Fronts in sepia. Horses, some with jockeys up.
Our original World Tobacco Issues Index records our anonymous set as simply : "FAMOUS RACEHORSES. Sm. Nd. (25). See RB.21/215-71.B" - though there is a cross reference to RB.21/215-71.A accompanying the Ogden`s version. I thought this may have been removed in our updated version, but no, the text is exactly the same.