Trainers Mark Pitman and Lisa Williamson were fined £200 by the Jockey Club disciplinary committee for the confusion that arose over the identities of Harem Scarem and Herman Sherman.
Williamson entered what she thought was Harem Scarem to run in a hurdle race at Carlisle in October, but the racecourse vet noticed that the horse's markings were different to his passport.
The horse, who was immediately withdrawn, was found to be an Irish import, subsequently named Herman Sherman, a four-year-old half the age of the real Harem Scarem.
Harem Scarem was then found to have been in a field in Williamson's Chester stable since his arrival from Ireland last year.
Pitman had saddled what he thought was Harem Scarem to a debut win last season at Bangor. The horse, which in fact was Herman Sherman, returned to Williamson for this season to join the real Harem Scarem.
Etienne Pollet, trainer of the legendary Sea Bird II and a host of other champions, died last weekend at the age of 88.
Widely regarded as one of the greatest racehorses that ever lived, Sea Bird II won the 1965 Epsom Derby and Arc de Triomphe.
Other top class horses trained by Pollet were La Sorellina, Hula Dancer, Never To Late, Right Royal V, Vaguely Noble, Grey Dawn and Gyr.
Alan King, assistant to David Nicholson, has been cleared to take over the training licence at Jackdaws Castle from tomorrow, when he could have his first runners at Sandown.