Blake Shinn's hopes of a first Cox Plate have been thwarted by a careless riding suspension out of Sunday's Seymour Cup meeting.

The jockey was outed for eight meetings for causing interference to two other runners in the early stages of the Seymour Cup won by Turn Me Loose, a Murray Baker-trained stablemate of Saturday's Caulfield Cup winner Mongolian Khan.

Shinn, who rode the unplaced Madam Gangster, will miss the ride on either Preferment or Winx in Saturday's Cox Plate.

Hugh Bowman has first choice of the Chris Waller-trained pair.

Champions Day at Ascot has also been costly for last year's Cox Plate and Melbourne Cup winning rider Ryan Moore and Singapore-based Australian Corey Brown.

Moore was outed for four meetings which include Melbourne Cup day.

Under British rules he can apply to have the ban deferred for Group One days and is likely to do so to at least ride at the Breeders' Cup meeting in Kentucky on October 31.

Moore won the 2014 Cox Plate on the Aidan O'Brien-trained Adelaide and Melbourne Cup on Protectionist.

Brown, winner of the 2009 Melbourne Cup on Shocking, was in England to ride Singapore's Emperor Max in the Champions Sprint won by Muhaarar.

The Stephen Gray-trained Emperor Max finished seventh with Brown outed for two days, October 31 and November 3.

The Seymour Cup win by Turn Me Loose capped a memorable week for his Kiwi trainer Murray Baker and jockey Opie Bosson.

It was Bosson's third winner from as many rides in Victoria in the past week.

He took out the G3 Ladies' Day Vase on the Danny O'Brien-trained Miss Rose De Lago last Wednesday at Caulfield and then produced a gem of a ride to win Saturday's Caulfield Cup on Mongolian Khan.

Turn Me Loose, a New Zealand G1 winner, justified his favouritism in Sunday's Seymour Cup after Bosson allowed him to work to the lead from his wide barrier.

"I wish they were that easy all the time," Bosson said after the win.

"He over-raced quite hard throughout the race and was really running.

"I didn't know if he was going to keep it up, but he's a good horse and he's still got a lot of improvement in him."

Bosson has won more than 40 Group One races during his career with Mongolian Khan's Cup win his third in Australia.

He won the 1998 VRC Oaks on Grand Archway and this year's Australian Derby on Mongolian Khan.

Bosson hasn't ruled out becoming a more permanent fixture in Australian racing now that he has his weight under control.

"If I got the opportunity I'd definitely come," he said.