"McCance's paintings in the 1920s were unusual in that he was one of the few Scottish artists who embraced the cubist, abstract and machine-inspired arts movements that spread across Europe following the First World War."
That said, my judgment is that he was a journeyman modernist who did little more than follow Modernist stylistic practices as they changed over time. Perhaps you will disagree. My case is stated in the following images.
He was about 22 years old and perhaps completing his art studies.
Modernist background, but otherwise conventional.
Now he is full-bore Modernist.
Probably his wife.
She too was an artist.
A dip into Cubism/Futurism.
... of a sports event? An election?
A late creation. McCance was a pacifist and jailed for that during the Great War.