Born on 13 July 1905 at Petone near Wellington in New Zealand, he was the son of Henry Lionel Ramsbottom-Isherwood and Lilian Catherine née Kelly.

[1] Commissioned into the New Zealand Rifles as a Second Lieutenant in 1924, Isherwood emigrated to the United Kingdom to train as a pilot in the Royal Air Force.

Besides training the Soviet pilots and ground crews, the wing claimed 15 enemy aircraft destroyed plus four "probables" and seven damaged, for the loss of one Hurricane in combat.

Isherwood compiled a lengthy signal stating that the journey was likely to take three months, that no rations or winter clothing were available and that there was a considerable danger of being overrun by the advancing Germans.

153 Wing, a much larger fighter force which was due to be sent to Russia in late 1942 but the plan, Operation Jupiter, was abandoned, perhaps because of the heavy losses to the Arctic convoys.

On 24 April 1950, he took a Gloster Meteor IV jet fighter for a test flight but ran into a severe snowstorm, crashed near Tonbridge and was killed.