Mackinlay was born in Spain to a Spanish mother and Scottish father. He studied at Perth Technical School in Western Australia under J.W. R. Linton in 1910-1912. Linton thought him “the most successful student of all those who passed through this school.” He later studied in London at St Martin’s. (http://books0977.tumblr.com/post/143775997237/laurie-and-theresa-the-artists-daughters-miguel)