Dual Grand National-winning trainer Nigel Twiston-Davies is “due” another winner, according to jockey Daryl Jacob.

He should know, having partnered Neptune Collonges to success in 2012, giving Paul Nicholls his sole triumph to date in the Aintree marathon.

Jacob, who returned to the saddle last month after breaking his hip in a fall in mid-December, feels Good Boy Bobby, winner of the Rowland Meyrick Handicap Chase at Wetherby on Boxing Day, can give Twiston-Davies a third National following those of Earth Summit (1998) and Bindaree (2002).

Simon Munir and Isaac Souede own the nine-year-old, along with Kildisart and Class Conti, who will also line up in the 40-strong field for the iconic four-and-a-quarter-mile handicap chase.

The trainer's son, Sam, will ride Class Conti for Willie Mullins, and Jacob is back aboard Good Boy Bobby, with whom he won a Listed handicap at Wetherby on his seasonal debut in October.

Jacob said: "I'm very much looking forward to riding him. I came up on Wednesday to walk around the track with my wife and kids. Looking at the track this year, I think the race is really suited to him.

"He's a horse that I feel, with the race getting closer and closer, I'm getting more and more confident about his chances. I think he'll take to the fences really well. Nigel is due a Grand National winner and there are lots and lots of positives.

"The ground is going to be in his favour. I don't think the trip is going to be a problem and I'm really looking forward to it, actually.

"I think I finished sixth on Ucello Conti for Simon and Isaac (in the 2016 renewal) and I think this lad can run above and beyond that, so I'm hopeful of a very good run from him."

County Kildare trainer Martin Brassil is no stranger to the Grand National. He saddled Numbersixvalverde to victory in 2006 and feels Longhouse Poet could bely his inexperience and get in the shake-up.

Longhouse Poet won the hugely competitive Thyestes Chase over three miles and one furlong at Gowran Park in January, relishing the soft ground.

Brassil said: "He is fine. We are really looking forward to the race. He has only had six runs over fences, but he is a good, sound jumper and the ground will be fine for him.

"He won the Thyestes nicely, albeit narrowly, but there were some good, touted horses in it, such as Escaria Ten (who reopposes).

"You'd be hopeful, if he finished in the first four or five – we'd be over the moon.

"You would, of course, like to win it again. It is a great race to be involved in."

Freewheelin Dylan is already a National winner, having taken the Irish version at Fairyhouse last April.

Though he has failed to finish in both starts this season, his trainer, Dermot McLoughlin, is hoping the better ground at Aintree will see him return to his best.

"He needs a bit of luck and I hope we didn't use up all the luck last year," said McLoughlin. "He seems in good form. All is good. I'm happy.

"His form has been in and out since winning the Irish National, but he is a top-of-the-ground horse. He is a summer horse and I think conditions over there will suit him. He enjoys his jumping.

"He is rated 147 and so it won't be easy. I'm hoping to win, of course, but a good run would be good. If he gets into a rhythm like he did in the Irish National, jumping-wise, if he takes to it, he should run well.

"We have been over there a few times and we were third in 2016 with Vics Canvas, so we have a view on what it takes.

"This lad is something similar. He is not over-big and I would have liked to have taken six or seven pounds off his back, but what can you do?"

"We are putting cheekpieces on, just to see if we can tweak something.

Discorama was seventh to Minella Times last year and trainer Paul Nolan feels he could have been closer with a smoother build-up.

"He had a wind operation," said Nolan. "It was sort of a last-ditch wind operation and once we got him back, we couldn't get him a prep run. He went to Aintree without one and thus he didn't get home.

"He looked to be travelling very well at the third-last and just didn't get home – and that is not like him. Normally, he goes to the line.

"I'm hopeful that if he gets the same luck in running as he did last year, and he jumps as well and if he could find a clean passage as he did last year, he will run a very respectable race."

He added: "You need to be so lucky and need so much luck in running.

"There should be no horse lower than 10-1 or 14-1, because there is so much luck involved – unless you had something that was bomb-proof that could make the running and stay out of trouble. How many horses could do that over that distance?"

Owned by Andrew Gemmell of Paisley Park fame and Thomas Friel, the nine-year-old was narrowly beaten in a competitive three-mile chase at Fairyhouse on his last run.

"We are putting cheekpieces on just to see if we can tweak something," Nolan added.

"We were very happy with the way he travelled in the race last year, and we thought at Fairyhouse he ran in snatches a bit.

"He looked like he should have won the race and still didn't, but we just thought we'd try something as there is no point regretting it afterwards.

"He did a bit of schooling with them on the other day and I'm not saying it made any difference, but hopefully they won't do any harm, anyway."

Peter Scudamore's eight jump jockey titles did not include a National win, yet he has been involved as assistant trainer to three winners since his retirement from the saddle.

He and partner, trainer Lucinda Russell, landed the prize in 2017 with One For Arthur, and they are represented by Mighty Thunder, who won the Scottish National last year.

"When I was with Nigel (Twiston-Davies), we had Earth Summit and Bindaree, and with Lucinda we had One For Arthur. It is a funny word 'retire'. I've moved on from being a jockey and have been incredibly lucky," said Scudamore.

"I thought I'd come up here to Scotland for an easy life, but Lucinda won't let me get away with that!"

Connections hope a wind operation will see Mighty Thunder in a better light than when pulled up at Musselburgh in February.

"He wouldn't want the ground too soft," said Scudamore. "He would have a chance at his best. He will have to produce his best, but he is a Scottish National winner and Scottish National winners have a good record in the race. He stays and he jumps. Then it depends on the class of the others.

"I thought he ran a good race at Wetherby first time. Then it was heavy at Aintree and we didn't run him, then it was heavy at Chepstow and we shouldn't have run him.

"He gargled at Musselburgh when he clearly cantered to the front and stopped. I think, hand on heart, he would have won.

"So he has had his throat lasered and it is just if that has worked now. I just don't think some of those horses will want softer ground."

Kildisart was runner-up in the Ultima Handicap Chase at Cheltenham two years ago but has had just three runs since, the last of those coming when a fine fourth in the Greatwood Gold Cup at Newbury off a 462-day break.

The 10-year-old, who will be ridden by James Bowen, is trained by Ben Pauling, who hopes it is first time lucky in the big race.

Pauling said: "He is in great order. It is always a life-long ambition to have a National runner when you are a trainer and this is our first, so we are really looking forward to it, as you can imagine.

"He has been in great order at home and his prep run was flawless as far as we were concerned, and so we are very much looking forward to it.

"I think he will stay every yard of the trip. He jumped beautifully when we schooled him over the National fences last Friday and we are in a really good place with him.

"We know we need luck in running, but I think he goes there as an exciting horse. I think he ticks a lot of boxes."