The Jockey Club will undertake a review of the situation with overseas Group One engagements that cost the club tens of millions in turnover yesterday when major drawcards Joao Moreira and Zac Purton were stranded in Taiwan for the day instead of riding at Sha Tin.

With chief executive Winfried Engelbrecht-Bresges and executive director of racing Bill Nader in Paris attending the Prix de l'Arc de Triomphe race meeting and International Federation of Horseracing Authorities conference, there was no definitive answer yesterday other than to say the club would look at its policy of releasing jockeys for Group One events.

"We missed two of our leading riders today and this disruption, with so many changes, is unsatisfactory to our customers, who spend many hours preparing for a race meeting. We will need to review these arrangements for the future," said Tony Kelly, the executive director of Racing Business And Operations.

Their absence cost Moreira one winning ride and another of his mounts was sensationally scratched at the barriers as a hot favourite, forcing the Club to return HK$71 million in bets on Team Fortune, but the two jockeys are also the subject of hundreds of millions a day in bets.

The Jockey Club had to abandon the Jockey Challenge - which would normally hold upwards of HK$10 million - and had to return all early bets on it but the real cost of the absence of Moreira and Purton is inestimable. Turnover was down by HK$77 million on last year's comparison meeting but the bleak weather will have made a contribution to that as well.

Moreira and Purton rode at Sydney's Randwick racecourse on Saturday before boarding a 10pm flight back to Hong Kong and that flight arrived as scheduled early yesterday morning but was unable to land due to strong winds at Chek Lap Kok airport and, after three aborted landing attempts, was diverted to Taipei.

The jockeys were able to get on to a flight scheduled for early afternoon but that in turn was unable to leave for several hours due to a backlog of flights and Hong Kong's champion jockeys of the past two seasons were still in Taiwan hours later.

Replacement riders were sorted out and their absence did allow Gerald Mosse to pick up a winning ride for his retained stable, part of a Manfred Man Ka-leung double, when the Frenchman replaced Moreira aboard Regency Darling in the fourth race.

Regency Darling drew well, enjoyed a comfortable trip through the race and duly saluted to break his maiden status.

"The horse was very green last season and to be honest he is still learning about racing but the jockey did a very good job from a nice draw," Man said. "I was only worried about him handling the soft ground when the rain came because he is a big horse and that can be a problem."

Man had also won half an hour earlier with Class Five battler Everyone's Choice (Neil Callan), who also used an inside draw to his advantage.

"I don't think he minded the sting out because the track was like that the other day that I won on him last season. He's just a very genuine sort of horse and that takes them a long way in that grade," Callan said.