The Irish challenge for the Randox Grand National looks set to be at a record high level this Saturday when as much as 75% of the field could be supplied by Irish trainers. Willie Mullins and Gordon Elliott will be the chief contributors, but there is also a significant challenge from the mid-to-smaller level yards.Meath-based but Kildare native John McConnell has shaped the whole season of his inmate Mahler Mission around an Aintree bid and the nine-year-old will go to Liverpool with a big chance.