The artist studied at Chelsea, the Academie Colarossi in Paris, and briefly at Newlyn in 1919.  He is identified as enrolling in classes at the FORBES School, by Green in her study Posing the Model. 

Soon after WWI Lett-Haines formed a firm friendship with Cedric MORRIS, and together they would later found the East Anglian School of Painting and Drawing. Frank DOBSON and Alec George WALKER were also companions during their time in Cornwall, and Morris attracted visitors such as Wyndham Lewis and McKnight Kauffer.

Both Lett-Haines and Morris were enthusiastic and lively, both in work and play, and their social lives in West Cornwall were boisterous and active - sometimes to a level unacceptable amongst the other more conventional artists still present. Even the indefatigable Alfred James MUNNINGS found reasons for objecting to their behaviour. (See entry for Cedric MORRIS for outline chronology, after the two friends departed Cornwall in 1927.)