From 1962 until 1964 her captain was Richard Trowbridge, who was later promoted to Rear Admiral and served as Flag Officer, Royal Yachts from 1970 until 1975, and in retirement as Governor of Western Australia from 1980 to 1983.

In 1966 she completed a long refit and modernisation of all her sonar and anti-submarine equipment[1] at Rosyth Naval Dockyard, and then became employed mainly in anti-submarine training duties, first in the Londonderry Squadron and then from 1969 in the Portland Training Squadron.

[2] Sir Robin Knox-Johnson, who in 1968 was the first person to perform a single-handed non-stop circumnavigation of the Earth while also winning the Sunday Times Golden Globe Race, was a watch-keeping and communications officer on Duncan from January to April of that year.

[3][4] In 1970 Duncan was again present at Portsmouth Navy Days, as part of the Portland Training Squadron.

[1] During the early 1980s, Duncan served alongside the frigate Eastbourne as harbour training ship at Rosyth Dockyard for the marine engineering artificer apprentices from the shore base HMS Caledonia.