Grogan was one of the Edwardian sailors abducted from Earth by the Eternals to crew the Shadow. He was in the crew room when the Fifth Doctor and Turlough came aboard and was introduced to them by Jackson. When the crew received the summon for rum rations, Grogan made a hurried exit, telling Turlough he'd see him later.
He was among the crew who took the drugged rum that made them accept being in space and wearing pressurised suits. He was returned to his own time at the conclusion of the race. (TV: Enlightenment)
Behind the scenes[]
Pat Gorman is visibly playing a crewmember aboard the Buccaneer in part four but it seems unlikely this was Grogan.