Nicky Henderson believes Roberto Goldback has a decent chance in the John Smith's Grand National if he can transfer his liking of the big fences at home to the real thing.

The former Irish-trained gelding has pleased his trainer the way he has taken to the Aintree-style jumps as part of his preparation for the big race on Saturday.

"Everything has gone really well. He's been consistent all season. He just loves good ground. He had to run in some soft ground a couple of times. He's in good form. We practised him at home on Aintree style fences and if he goes as well on the day as he has been practising it will be great," said Henderson.

The Philip Hobbs-trained Quinz has been ruled out of the race following an unsatisfactory scope.

The nine-year-old made a fine comeback after a lengthy absence when fourth in the Racing Plus Chase at Kempton in February and had been saved for a second crack at the National since, having been pulled up when well fancied for the great race two years ago.

Hobbs' stable jockey Richard Johnson had already opted to partner Balthazar King, but said: "I had already chosen to ride Balthazar so it will have no bearing on my decision but it's a shame. I hope another race can be found for Quinz before the end of the season.

"The ground is a big factor to Balthazar King and it looks like it has come right for him. He's jumped around the cross country course at Cheltenham well and I'd hope he'd take to the fences, but you can never be confident."

Quinz's defection means Nigel Twiston-Davies' Major Malarkey is now guaranteed a run in the four-and-a-half-mile contest. Twiston-Davies, who also has top-weight Imperial Commander, said: "It's great he's got in the race. He's a stayer, he jumps well and he'll run really well. Tom Scudamore rides."

Another who will not be running is Ferdy Murphy's Poker De Sivola who was officially scratched late on Wednesday afternoon.

Murphy said: "We had him scoped earlier today and he's just not quite right. There's nothing we can do about it but you can't run them if they're not right."

The news means that the Jo Hughes-trained Soll, who was 42nd on the list, is now guaranteed a run.