He continued racing for two more seasons after his Gold Cup run, his last race being in November 1981. But there were no more wins after his multiple successes in 1979/80.
I’ve no info on his retirement, but would assume that he remained in the care of his owner/breeder Pam Neal, who also trained him under permit for his last five seasons. She had a property on the edge of Dartmoor, where Mac Vidi was allowed out every day while she was training him.
One reason I was always interested in him, apart from that run of wins, what that his sire, Vidi Vici, was foaled in 1947, same year as me! In the detailed entry in Chasers and Hurdlers 1979/80, they allude to the age spread of the family by reporting that Vidi Vici had won a staying handicap at Goodwood in 1950, ridden by an apprentice claiming 5lbs – L Piggott.