John Barbirolli
In 1927 he took over a concert that Thomas Beecham would have conducted with the London Symphony Orchestra.  He conducted other English orchestras including the Hallé Orchestra and was becoming very well known.  He could learn music very quickly.  In the 1930s he made many recordings with the London Symphony Orchestra and London Philharmonic, accompanying concertos with famous soloists such as Fritz Kreisler, Jascha Heifetz and Arthur Rubinstein.