I’ve had some luck in researching Raymond MacIntyre’s portrait of Haraldur Hamar c 1923, he’s the distinctive looking man with the great brows.
Hamar was born in Reykjavik in 1892. He was the son of a poet and a headmaster, Steingrimur Thorsteinsson, and later changed his name from Thorsteinsson to Hamar.
A Reference Librarian at the National Library of Iceland found two articles about Hamar, you can see them under the following links. They are of course in Icelandic, but we can see that Hamar was painted more than once.
In Osbert Sitwell’s biography: Left Hand, Right Hand!: an autobiography, London 1951 in the fifth volume he writes about Hamar, who associated with the Bloomsbury group in London, they called him Iceland.
I’d love to catch up with any Icelandic speakers, is there someone out there keen to translate this article?