http://www.designation-systems.net/non-us/spain.html says that the airplane for Spain was designated as CASA/Heinkel CH-101 and its military designation was to be the C.7.
This is what I have found on the Heinkel's works in Spain in the "Secret Messerschmitt Projects" by Willy Radinger and Walter Schick:
I would be really grateful for any info on the matter, including Internet links or titles of books etc. that cover the subjects. Any pictures would be appreciated very much.Ernst Heinkel [...] worked in Stuttgart on a light-fighter design which apparently mirrored the ideas of the leaders of the Spanish Air Force more so than those of the somewhat heavier Messerschmitt aircraft.
The delta-winged fighter HE C-101 from the Heinkel Chief Engineer Siegfried Günther was based on the experiences he had gained with the design of a fighter-bomber for Egypt.
Thanks in advance,
Piotr