 From 1921, his only principal role was Annibale, but he occasionally filled in for Derek Oldham as Tolloller in "Iolanthe", before retiring from the stage in April 1922.Blackmore was then employed by D'Oyly Carte to coach the Company's professional understudies in their roles.He was appointed as D'Oyly Carte's stage manager for the 1922–23 season, but, coming into "uncomfortable conflict with the artistic temperament", he was replaced the following season by Frederick Hobbs.