Having failed in service the previous day at York, with the 1E11 08:50 Aberdeen - King's Cross service, 55021 (D9021) "ARGYLL & SUTHERLAND HIGHLANDER" has made it back to home depot Haymarket on the 20th April 1976. The loco was called to works just two days later for classified overhaul, which came in the form of a Heavy General Repair. 55021 was one of only five members of the class to be treated to a HGR and was out of traffic at Doncaster until January 1977.