After dropping out of school early, he went to work for a publisher before using family contacts to secure a job with organ builder Ivor of Hill, Norman & Beard in the 1930s.
[3] Mander started working independently in 1936, and found employment with the diocese of London.
[4] With the onset of World War II, Mander, who saw several of his early works destroyed under German bombardments, first became an auxiliary fireman before joining the Royal Artillery in 1940.
[4] In 1946, he returned to civilian life and resumed his partnership with the diocese of London, restoring several organs damaged during the war.
[3] His crowning achievement was the rebuilding of the organ in St. Paul's Cathedral, between 1972 and 1977, for which he was appointed in the New Year Honours 1979 as a Member of The Order of the British Empire.