Trainer Chris Waller has warned the lead-up race that is usually the best guide to the Group One BMW might this year be a confusing pointer to the $1.5 million weight-for-age contest.

Almost half of the past 31 BMW winners have come through the Ranvet Stakes at their previous start and there's every chance the trend will continue at Rosehill on Saturday.

But Waller is preparing for form turnarounds from at least two well-beaten Ranvet runners, including his weight-for-age winner Foreteller.

Silent Achiever ran to her best to edge out Carlton House almost a fortnight ago, with predictions of a match race between It's A Dundeel and Fiorente falling flat.

It's A Dundeel took the minor placing with the Gai Waterhouse-trained Fiorente finishing seventh and Foreteller eighth in a performance that left Waller searching for answers.

"My first thought about Foreteller was that he was disappointing," Waller said.

"I was a bit confused by what happened in the race but after looking at it again it was obvious the tempo didn't help a lot of horses and I think there might be a few form reversals come out of it.

"The speed was on then it dropped right off before they sprinted up again and it didn't help Foreteller.

"Foreteller is one horse who can improve and so will Fiorente."

Bookmakers agree with Waller's line of thinking with Fiorente the $2.90 favourite to make it three Australian Group One wins.

In stepping up to 2400m in the BMW, Fiorente will race beyond 2000m for the first time since his Melbourne Cup victory last year but he galloped strongly under work rider Mark Newnham at Randwick on Tuesday.

Fiorente is likely to strike a rain-affected track for the first time in 11 Australian starts but he is proven in the ground in England.

His best win for trainer Sir Michael Stoute was posted on a slow track over 2400m in the Group Two Goldsmith's Stakes at Newmarket.

It's A Dundeel is out to $4 after a week of vet checks.

The latest inspection came in front of Racing NSW vet Dr Craig Suann at Warwick Farm on Friday morning and he cleared the four-year-old to take his place in the field.

It's A Dundeel has been working in special shoes which are thought to have caused lameness in his front legs.

The entire has since galloped freely and stewards have confirmed the five-time Group One will wear standard racing plates in the BMW.