here. He worked regularly for the publisher Editorial Ferma in the 1960s, producing covers for books in the early 1960s and for the comics El Santo (based on The Saint, 1965) and Extra combate (1965-67). His full name was Joaquin Chacopino Fabre... but is he our mysterious "Chaco"?
Update: 16 August 2015
The answer to the above question is "Yes". I received a note from Jordi Chacopino, who tells me that his father was indeed "Chaco". He worked extensively for publishers in Germany and Italy as well as the UK in the 1960s. Working through Bardon Art, he lived for some time in England, but missed his family – his wife and three sons, who had remained in Barcelona & ndash; and returned to Spain.
"Chaco" died in 2014.