Dunboyne & Mark added to Derby entries Dunboyne Express and Aidan O'Brien's recent Curragh maiden winner Marksmanship are among 12 horses entered for the Investec Derby at the second entry stage. They are hoping to follow in the footsteps of last year's winner Workforce, the first horse to win the Classic having not been in the original entries. The extra dozen have paid £8,000 for the option of running at Epsom on June 4. Others added include Godolphin's Casamento and Dubai Prince, the Henry Cecil-trained duo of Picture Editor and the unraced Midsummer Sun, Ed Dunlop's Native Khan. Kevin Prendergast decided to supplement Dunboyne Express after his easy comeback win in the Group 3 Leopardstown 2000 Guineas Trial Stakes over a mile. "It would be on the agenda, depending on how he progresses in the Irish 2000 Guineas - if he runs a good race at the Curragh, the Derby would have to be considered," said the veteran Curragh trainer. "His pedigree says he should get a mile and a half but it's not written in stone. "His dam is a half-sister to the Oaks winner Love Divine, so he's also related to the St Leger winner, Sixties Icon. Shamardal got 10 furlongs and he was a real class horse, so there's every chance that Dunboyne Express will get the trip." The next and final entry stage costing £75,000 deadlines at noon on Monday, May 30.