Thank you for that David. Looking further I have found a document, ‘The Marriage of Mathematics and Biology’ by John Maynard Smith, that includes this paragraph.

‘In normal times, I would probably have switched from engineering to biology while at Cambridge. But times were not normal. The war broke out, and a half trained engineer had no choice but to complete his training and enter industry. I became an aircraft stressman reponsible for ensuring that the aircraft structure did not break under loads imposed. I worked at Miles Aircraft, a company that built training aircraft. I worked very hard, but I do not think I made any useful contribution to Britain’s war effort, although aeroplanes I worked on were widely used after the war.
Finally in 1947 I left the aircraft industry and returned to university to study biology.’