World Hurdle poser for Twiston-Davies Paul Nicholls admits it was a "close call" for stable jockey Sam Twiston-Davies over which of the yard's two runners he will ride in the Ladbrokes World Hurdle at Cheltenham. Following news More Of That will not be defending his Festival title, the Ditcheat-trained pair of Zarkandar and Saphir Du Rheu sit at the head of the ante-post market, with plenty of bookmakers unable to separate the duo. But Sam Twiston-Davies had already pledged his allegiances to Saphir Du Rheu, who booked his slot in the race when landing the Cleeve Hurdle following a disappointing stint novice chasing. The fact he has returned to hurdles from fences evokes memories of Nicholls' star stayer Big Buck's, who won four World Hurdles for owner Andy Stewart, in whose colours Saphir Du Rheu also runs. Big Buck's crashed out in the Hennessy before going on to World Hurdle glory and while he never returned to fences, Nicholls expects Saphir Du Rheu to eventually make his mark in that sphere. The champion trainer said: "Saphir Du Rheu is still a young horse. We put him in the World Hurdle as it's wide open. "He won the Cleeve Hurdle and stayed on really strongly up the hill and his jumping was very sharp. "There is a lot of improvement to come and we are very pleased with him. Sam has decided to ride him and that was a close call. "While Big Buck's never jumped a fence, this lad will and we will do that again soon." Twiston-Davies was aboard Zarkandar when he suffered a shock defeat in the Long Walk Hurdle at Ascot before Christmas but Nicholls believes he also has strong claims. The eight-year-old finished fourth in the race last year and Nicholls expects him to put that Ascot eclipse well behind him. He said: "Zarkandar just pulled himself up in front at Ascot and if Sam rode him again, he would have done things a bit differently. "He is so much better when fresh and this year we trained him just for this race. He worked well in a racecourse gallop at Wincanton 10 days ago. "I think he's got a fantastic chance as the more competitive race will give him a better lead into it, so we do not have to hit the front too soon. "He's a talented horse who is in good order." Nicholls also holds a strong hand in the Betway Queen Mother Champion Chase, with Dodging Bullets and Mr Mole in the mix after winning their prep races. Dodging Bullets supplemented his Tingle Creek success by claiming the notable scalp of the returning Sprinter Sacre in the Clarence House Chase at Ascot last month. While there were obvious excuses for Sprinter Sacre as he returned from a heart problem and a long absence, Nicholls felt his charge had plenty more in hand than the three-length winning margin suggested. He said: "He (Dodging Bullets) probably deserves to be favourite for the Champion Chase. "The nice thing about his win at Ascot was that Noel (Fehily) felt he had plenty left in the tank. "What he likes is nice, soft ground as he's a really strong-staying two-mile chaser. "He's a good, tough galloper who is in really good order. "Last year he was quite mentally immature, but he's grown up now and is so much more relaxed." Mr Mole is a relatively late arrival on the Champion Chase scene but he will line up on the back of four successive wins, most recently in the Game Spirit Chase at Newbury. Nicholls sent Master Minded to win that race before his Cheltenham success in 2008 and hopes the JP McManus-owned seven-year-old can emulate that performance and give the retiring Tony McCoy a final victory in the two-mile feature. "Mr Mole has followed the same route as Master Minded and hopefully that's a good omen," he said. "He is hugely talented and is mentally a lot more mature. "AP has worked out it's better to bowl along on him. He's not ungenuine, just a bit of a character "He cantered into the race last time at Newbury and won very well. "AP has got a lot of faith in him now and I think he will run a big race." Nicholls also has Vibrato Valtat to look forward to in the Racing Post Arkle Challenge Trophy Chase, although the ante-post market suggests he is facing an uphill battle against odds-on favourite Un De Sceaux. He said: "Vibrato Valtat is probably one of the most improved horses in training. "He's a great example of how a breathing operation has worked. "He needed his first run over hurdles this year and he should have won at Cheltenham. We were very impressed at Warwick, he jumped and travelled well. "Apart from Willie Mullins' horse, we would have an outstanding chance. "But it's all about the jumping and they are going to be going a good gallop, which won't do him any harm. "You can ride him more prominently now and you don't have to worry about being in front too soon."